Clizio Nioi was born on 15 July 1915 and was from Terranova (Sassari).

On 1 October 1936, he was commissioned (in Servizio Permanente Effettivo).

In June 1940, Tenente Nioi served in the 80^a Squadriglia, 17^o Gruppo C.T., which was equipped with Fiat CR.32s.

In the afternoon on 23 June 1940, Palermo was bombed by four Glenn-Martin GM 167Fs from GB I/62 and three from GB II/62. The French bombers aimed at the harbour but many bombs fell in the city itself, killing 25 civilians and wounding 125 more.
The returning French crews didn’t report any presence of Italian fighters but one Glenn crashed before coming back to base and another crash-landed at Canrobert without losses among the crews, reportedly suffering mechanical breakdowns.
Another bombing of Palermo was made by five LeO 451s from GB II/11, which had taken off in the late afternoon from Youks-les-Bains (aircraft n^o200 commanded by Colonel Chopin, n^o 201 commanded by Lieutenant Calmel, n^o 213 commanded by Lieutenant Zimmermann, n^o 144 commanded by Lieutenant Drougue and n^o 3005 commanded by Capitaine Bouyer). In fact, only Zimmermann and Calmel hit the intended target from an altitude of 5000 metres; Chopin returned early because of a breakdown, Bouyer attacked Marsala, while nothing was heard of Drougue’s aircraft that, forced to take off late, became immediately separated. In Fact it seems that LeO 451 n^o 144 returned at night, probably short of fuel and trying to force-land on a beach near Cap Bon it exploded, killing the crew.
From the Italian records we know that at 18:25, seven “enemy bombers” were discovered over Palermo at approximately 4000 metres, they attacked the harbour diving with the engines shut-down and achieved complete surprise. The CR.32s of the 17^o Gruppo tried in vain to intercept because of the late discovery and the height of their opponents. In the meantime, alarm was given also to the CR.42s of the 157^o Gruppo and the CR.32s of the 80^a Squadriglia, 17^o Gruppo, then detached to Trapani, in the hope of catching the raiders during the return leg of their mission. The fighters from the 157^o Gruppo scrambled at around 18:40 and returned one hour later without having seen any enemy while, flying north, two CR.32s of the 80^a Squadriglia, piloted by Tenente Nioi and Tenente De Tecini discovered an alone aircraft off Capo Gallo (slightly west of Palermo’s harbour). The aircraft was identified as a “Potez 63” and attacked by Nioi, who could benefit of a slight height advantage over his target. Nioi hit it, observing the French raider that nose dived engulfed in a thick cloud of smoke. Later ground observers reported that the aircraft had fallen into the sea and Nioi was credited with his first aerial victory. Finally, at 19:30, a last attack on Mazara del Vallo (an harbour very close to Marsala) was reported.
It seems probable that one of the French bombers, possibly the lone LeO 451 of Lieutenant Drogue was the machine attacked by Nioi.

He was promoted to Capitano on 6 February 1941.

The British offensive Operation Crusader was launched in North Africa on 18 November 1941. Italian reinforcements were rushed to Libya including the 17^o Gruppo, which arrived at Martuba on 25 November with their MC.202s and Capitano Nioi as CO of the 80^a Squadriglia.

At 15:55 on 12 December 1941, eleven MC.202 of the 17^o Gruppo (six from the 71^a Squadriglia and five from the 80^a Squadriglia), led by Capitano Aldo Felici, took off for troop protection between Gazala and Derna. At 16:00, at the height of 1500m., almost immediately after take-off, they clashed with an enemy formation estimated 30 Curtiss P-40 and Hurricanes strong, apparently directed to attack the landing ground of Martuba.
The Italians claimed no less than eight planes; one each by Capitano Nioi (80^a Squadriglia), Tenente Glauco Vatta (71^a Squadriglia), Sottotenente Renato Bagnoli (80^a Squadriglia), Maresciallo Marcello Lui (71^a Squadriglia), Maresciallo Pio Marsilli (80^a Squadriglia), Sergente Maggiore Mario Host (80^a Squadriglia), Sergente Maggiore Remo Broilo (71^a Squadriglia) and Sergente Egidio Buogo (71^a Squadriglia). Two more were claimed as probables by Nioi and Tenente Emilio Marchi (80^a Squadriglia). Three MC.202 were hit in the cooling systems of which Capitano Nioi landed OK, Tenente Vatta (MM7871) crash-landed on base and Tenente Pierfranceco Conti (MM7861) belly-landed and was slightly wounded. A fourth Macchi was slightly damaged. The formation landed at 16:35 (or alternatively 16:55) and the Italian pilots had expended 3680 rounds of ammunition.
Three MC.202 of the 81^a Squadriglia (6^o Gruppo), led by Tenente Giorgio Falchi, scrambled at 16:10. Once they reached the height of 1,000m, at 16:20, they discovered ten Hurricanes strafing the German sector of Martuba. The Macchis jumped the enemies and Tenente Falchi damaged two of them using 80 rounds of ammunition and in turn he was hit by three rounds. The Italian fighters landed at 16:50.
Between 16:00 and 16:10, 14 Bf 109s from III/JG 53 claimed six Hurricanes and a P-40. These were claimed by Oberfeldwebel Hermann Neuhoff of 7./JG 53 (Hurricane at 16:00 and P-40 at 16:10), Unteroffizier Erich Schmidt of 7./JG 53 (Hurricane at 16:00), Leutnant Siegmund Hosnedl of 7./JG 53 (Hurricane at 16:00), Oberfeldwebel Werner Stumpf of 9./JG 53 (two Hurricanes at 16:03 and 16:05) and Leutnant Wolf Schaller of 9./JG 53 (Hurricane at 16:10).
On the Commonwealth side, it appears that at 15:15, nine Tomahawks of 4 SAAF and seven from 2 SAAF Squadron, had taken off as top and close cover respectively to a formation of six Blenheims from 14 Squadron targeting the Derna road (they later reported the attack to the escort with heavy losses of the latter). The South Africans of 4 SAAF Squadron were engaged for 30 minutes with twelve enemy fighters and three Bf 109s were claimed (Captain Andrew Bosman (2) and Lieutenant Douglas Golding) plus two damaged by Bosman, while Lieutenant Lewis Otto Beatty Player (SAAF no. 102848V) was lost (Tomahawk AN351; according to some sources, the Bf 109 that shot down Player was then shot down by Golding). Two more Tomahaks were damaged (including Bosman’s). 4 SAAF Squadron landed again at 16:55. Captain Bosman reported that while on top cover he sighted a number of Bf 109Fs:

‘I broke away to attack, I informed the Sqn. leader and a fight ensued.
I surprised 2 enemy aircraft and opened fire on each in turn. I am certain I inflicted a fair amount of damage to each of these aircraft. I was forced to rejoin our offensive circle.
One of our aircraft was shot from below. The pilot spun from for about 3000 feet and recovered. He tried to climb back and I circled below to assist him. At about the end of the engagement I was attacked and as the enemy aircraft zoomed past me, I pulled in behind him and opened up. He stood on his tail and flicked over into a spin from which he did not recover. I saw him burn on the hilly ground below.
We rejoined the Blenheims on their way back, and 2 of our A/C including the pilot who had been shot up earlier on were far apart and behind on either side of the bombers. They were attacked by Me.’s from below. I tried to ward off these attacks and on one occasion I peeled off on an aircraft and as he turned and dived I shot him up. He dived head on toward the sea and did not recover. At this stage I proceeded to take cover in the clouds and as I broke cover I was engaged from below, sustaining damage in the tail, dashboard and wing of my aircraft.’

“Fired long burst at 109 F and saw smoke or oil or both pour from his engine. He seemed to go in a long dive. Saw what appeared to be glass house break away from M.202 after burst. Two 109 Fs chased me down to 500 feet making alternate quarter attacks. I kept turning into each as he made his attack. E/A opened fire at very long rang, E/A broke away (possibly ran out of ammo).
I claim a 109 F probably destroyed and a M.202 damaged.”

“Engaged one M.202 with PO Humphreys and had a violent dogfight, no hits observed. Then two others attacked me, I turned inside one and saw a flash inside his fuselage and he dived away. The other meanwhile had been engaged by another Tomahawk.
Claim one 202 damaged, self no damage. Macchi dived vertically and the climbed straight up into sun. Very hard to hold the climb.”

“Two enemy aircrafts attacked No.2 Red Section by diving from above. These two a/c followed line astern. I turned in, fired on both and followed one down. The first - a 109 F - appeared to be hit near the cockpit as a flash appeared. When about 4000’ lower was still on his back. After following and losing a 109 I climbed to 12000 feet and was jumped by a 109 E (a Macchi?) which chased me down to cloud cover.”

“While on offensive fighter sweep over Tmini area 1300 ft (sic) E/A were reported 9 o’clock below and climbing. During the formation turn two aircraft collided. One of these turned in the direction of the base and dived for a cloud layer at 3000 ft. I turned and dived to follow him. While catching Tomahawk to escort to base ME 110 was sighted above flying towards me. Cloud base was 3000 ft. and E/A was just beneath. Pulling around into his tail from beneath flames came from wing root and fuselage after two bursts. I then lost sight of the a/c.”

On 28 March 1942, three MC.202s of the 6^o Gruppo (one from the 79^a Squadriglia and two from the 81^a Squadriglia) led by Tenente Palazzeschi, scrambled at 13:35 (returning at 14:30) to intercept a formation of enemy bombers and fighters over the airfield. (this action is recorded by the Gruppo’s Diary only)
Between 13:35 and 13:40, twelve MC.202s from the 17^o Gruppo (three from the 71^a Squadriglia, four from the 72^a Squadriglia and five from the 80^a Squadriglia), led by Capitano Nioi, took off after the same enemy formation.
West of Tobruk, only Tenente Bruno Ganda (81^a Squadriglia) was able to engage the enemy and claimed a P-40 shot down with the use of 250 rounds of ammunition.
Five pilots of the 17^o Gruppo engaged, claiming a P-40 by Capitano Nioi who also damaged a bomber west of Tobruk and three P-40s damaged by Sergente Maggiore Mario Host (80^a Squadriglia), Sottotenente Gastone Petrucci (71^a Squadriglia) and Tenente Mario Carini (72^a Squadriglia) (two of them subsequently upgraded to probables with the use of 1050 rounds of ammunition). The pilots of the 17^o Gruppo believed that the enemy bomber formation, escorted by around 30 P-40s, returned individually.
Three MC.200s from 150^o Gruppo, led by Sottotenente Giovanni Dell’Innocenti were on patrol over Martuba when the raid approached. They immediately engaged but one of the fighters (MM5827 flown by Sergente Maggiore Mario Angeloni of the 364^a Squadriglia) was shot down and the pilot killed.
The enemy aircraft were a formation of nine Bostons from 12 SAAF Squadron, escorted by nine Kittyhawks of 94 Squadron (take off 12:40 and landing 14:15-14:35) as middle cover, twelve Kittyhawks of 450 Squadron as top cover and finally a close cover of Kittyhawks of 2 SAAF Squadron. Martuba West was bombed from 11,000 feet; 35 bombs hit the target area and some of them exploded near planes dispersed on ground. A storage was set on fire. AA was intense and precise; two Bostons were heavily damaged and two more were slightly damaged while Observer Lieutenant Ian Ross was killed.
Immediately after the bomb release the formation was attacked by at least twelve Bf 109s, 450 Squadron suffered the loss of Sergeant W. J. Halliday (AK695/G); the pilot made a wheels-up landing in no man’s land wounded and was later recovered by the Army, 94 Squadron lost Pilot Officer 22-year-old Pilot Officer James Aitken Crosbie (RAF no. 101493), who was wounded, his fighter (AK858) was later recovered and classified Cat. II. During the combat, Flight Sergeant Eddie Edwards (FZ-V) saw frantic activity above him. He watched as the Bf 109s dived down and then pulled upward again. While most stayed high, some of them continued their dive into the path of 94 Squadron. As two passed in front of him, he fired several bursts of ammunition. The first Bf 109 made a steep climb and the other rolled over and headed west. He thought he might have hit the second Bf 109 but he made no claims, as he was not sure. 450 Squadron suffered two more fighters heavily damaged (Cat.II) plus a third obliged to force-land reportedly due to lack of fuel. (Cat II) while Squadron Leader Gordon Steege (AK692/C) and Sergeant N. H. Shillabeer (AK799/R) claimed a Bf 109 probable each; that of Steege was subsequently upgraded to confirmed. Sergeant Ian Nursey (AK668/H) claimed a probable MC.202 and Pilot Officer A. E. Kelsall (AK895/K) a damaged Bf 109. The pilots of 450 Squadron recorded being engaged from their arrival over the target until the return to base.
One of the two damaged machine was that of Sergeant E. J. Quirk (AK706), who returned and landed without flaps at 150 mph, with a big chunk of the left wing close to the flap lacking. Quirk was probably hit by a cannon shell from a Bf 109.
Strangely, 2 SAAF Squadron didn’t report any action even if the Macchis had reached the bombers. Feldwebel Günther Steinhausen of 1./JG 27 claimed a P-40 at 13:40 near Tmimi (possibly Halliday), so at least one victory was obtained by the 1^o Stormo’s pilots who were most likely the main responsible for the heavy opposition experienced that day by the Commonwealth units. The 1./JG 27 also lost Bf 109F-4 trop WNr 8716 during the day when it was hit in the engine during combat with P-40s. The aircraft ceash-landed at Tmimi and was destroyed to 90 % but the pilot was safe. At the end of the day 3 Wing ORB summed up: “A raid on Martuba is no longer a profitable transaction”.
The wounded Pilot Officer Crosbie was later reported to be with a field ambulance, and was said to be only slightly wounded, but on 5 April the news was received that he had died on the 4th.

On 3 April, both Gruppi of 1^o Stormo scrambled to intercept a formation of bombers escorted by fighters heading for Derna.
Nine MC.202s of the 6^o Gruppo (seven from the 79^a Squadriglia, one of the 81^a Squadriglia and one of the 88^a Squadriglia) took off at 10:15 led by Capitano Domenico Camarda (CO of the 79^a Squadriglia). Flying at the height of 4000 meters over Ain el Gazala, four Macchis reached the enemy formation and engaged the escort (whose planes were identified as P-46s – but obviously Kittyhawks). One of them was claimed shot down by Tenente Paolo Cattaneo (79^a Squadriglia) who saw his opponent landing hurriedly in Gazala. Maresciallo Giovanni Collovini (81^a Squadriglia) claimed a probable while Sergente Maggiore Amedeo Benati (79^a Squadriglia) claimed a damaged. Maresciallo Italo Bertinelli (79^a Squadriglia) in MM7860 was shot down in flames near the Gulf of Bomba and lost his life. The other pilots landed back between 10:50 and 11:15 after having used 1345 rounds of ammunition.
Eight MC.202s of the 17^o Gruppo (three from the 71^a Squadriglia and five of the 80^a Squadriglia) led by Capitano Nioi, took off at 10:30. The five MC.202s from the 80^a Squadriglia managed to engage twelve P-40s, claiming four shot down confirmed, one probable and one damaged. The confirmed victories went to Capitano Nioi, (who also claimed the probable), Maresciallo Bruno Castellani, Sergente Maggiore Mario Host and Sergente Maggiore Alvise Andrich. A sixth plane was claimed damaged by Tenente Renato Talamini. The Italian pilots were back at 11:20 and they had expended 1690 rounds of ammunition.
With this victory Capitano Nioi qualified as an ace, as the first pilot of the Stormo to reach this status during the conflict.
Twelve Bostons of 12 SAAF Squadron were in action over Derna escorted by four Squadrons. 2 SAAF and 4 SAAF Squadrons, each with six Tomahawks formed the close cover, 94 Squadron acted as top cover (they had taken off between 10:30 and 10:45 and returned between 11:50 and 12:10); and finally eight Kittyhawks of 260 Squadron, which had taken off at 10:30, as an extra top cover. Additionally, twelve Kittyhawks of 450 Squadron had taken off at 10:40 to cover the returning bombers. They were divided in two formations, one at 19,000 feet and a second at 17,500 feet. They directed over Bu El Bergasi, Gazala then stationed over Menelao bay waiting for the bombers. Finally, ten Hurricane IIbs of 274 Squadron had taken off at 10:50 for a diversionary sweep over Gazala, two of them had to return early for engine problems.
4 SAAF Squadron recorded that the bombing attack, performed on an east-west course from the height of 14,000 feet was quite accurate. 45 well dispersed enemy aircraft were counted on the airfield. In particular in the north-eastern corner of Derna were more than 20 enemy aircraft dispersed and the bombs were seen to fall south of them.
During the attack, eight Bf 109s were seen to take off from the southwestern corner of Derna, apparently alerted by heliograph signals from Martuba. 2 SAAF Squadron also noted the take-off of enemy fighters from Martuba but the two South African units weren’t engaged.
Immediately after the bombing attack, 94 Squadron was engaged by three Bf 109 of I/JG27, and Pilot Officer G. L. Usher (AK741) claimed a destroyed Bf 109E and this was possibly the Messerschmitt of Leutnant Julius Wildau of 3./JG 27 (Bf 109F-4 trop WNr. 8411), who crashed to death 2km west of Casa Cantoniera on Via Balbia. The 94 Squadron didn’t suffer any loss.
Subsequently, over Menelao bay, five miles north-west of Bomba, 260 Squadron claimed two Bf 109s (one by Flight Sergeant Thomas Hindle and one shared between Squadron Leader Osgood Hanbury (AK867) and Sergeant J. V. Carlisle). Then Flight Sergeant Hindle engaged a MC.202, 12 miles south south-west of Gazala and claimed it probably shot down. The 6^o Gruppo was possibly involved in this combat together with some Bf 109s, with the loss of Maresciallo Bertinelli while the Germans lost Leutnant Rainer who was obliged to force-land. After this, close to Gazala, Hindle was attacked by two Macchi MC.202s (probably from the 6^o Gruppo); the first one, after the attack headed west while the second engaged in an inconclusive dogfight. Finally, over El Adem, Hindle was attacked by two Bf 109, being able to shot at one of them without claiming any damage.
The fighters of 260 Squadron landed at 12:15 without reporting any damage at all even if the ORB of 4 SAAF Squadron noted that a Kittyhawk of 260 Squadron was heavily shot up but succeeded in landing back at base.
In the Gazala area, 94 Squadron lost 19-year-old Pilot Officer Richard Warwick Martin Moon (RAF no. 106647) (Kitthawk Ia AK942), who failed to return and the fighter (AK769) of Sergeant Musker, who was wounded, while Sergeant Ray Matthews (AK735) was obliged to force-land near Gazala due to engine problems in a situation that matched that described by Tenente Cattaneo, a fact that suggest the presence of the 6^o Gruppo in the combat.
In the meantime, 450 Squadron discovered the bombers that were coming back to base and saw higher two Bf 109s that failed to intervene. South of Gazala the Squadron headed south towards a combat already ongoing (possibly the already described action involving 260 and 94 Squadrons) and two of its pilots engaged two MC.202s and one was claimed damaged by Sergeant Ian Nursey (AK606/OK-B).
Between El Adem and Tobruk, 450 Squadron’s CO, Squadron Leader Gordon Steege (AK717/V), discovered three MC.202s flying lower and led his unit to attack. Two of the Italian fighters were claimed damaged; one by Steege and one by Sergeant Donald McBurnie (AK865/K. All the fighters of 450 Squadron returned unscathed even if one of them had been forced to return early with engine problems.
Then it was the turn of the Hurricane IIbs from 274 Squadron, which engaged Bf 109s and MC.202s, claiming three probables by Pilot Officer R. H. Hunter (Bf 109), Sergeant H. Garwood (Bf 109) and Sergeant William Marsh (MC.202), but suffering the loss of the plane of Sergeant A. E. Howell, who was wounded but was saved.
The diary of Sergeant William Marsh who was flying Hurricane IIb BD820/D recorded only Macchis (possibly the formation of the 17^o Gruppo):

“1 Macchi 202 damage: engaged by 6+, one of which turned on to Sgt. Presse, my No. 1. Pukka dog-fight for ten minutes, 202 looping and rolling, got in snap shots at bottom of loops. Broke off combat when a second 202 appeared – my ammo finished too. Sgt. “Tiny” Howell shot down.”

On 6 April, the 6^o and 17^o Gruppi scrambled to intercept a raid of bombers escorted by fighters over Derna. The 6^o Gruppo scrambled with six fighters (three from the 79^a Squadriglia, two from the 81^a Squadriglia and one from the 88^o Squadriglia), which took off at 08:10 and returned between 09:10 and 09:15 while eight fighters from the 17^o Gruppo (one from the 71^a Squadriglia and seven from the 80^a Squadriglia) scrambled at 08:20 and landed back at 09:40.
The fighters from the 6^o Gruppo had barely taken off when the Commonwealth formation composed of twelve Bostons escorted by many fighters stepped at different heights released its bomb-load on Derna El Ftehja. Only Capitano Domenico Camarda (79^a Squadriglia) and Capitano Dante Ocarso (88^a Squadriglia) were able to reach the raiders at the height of 4000m. Capitano Ocarso reported that he reached the enemy formation over Gazala and attacked even if flying at inferior height and heavily outnumbered. He claimed a P-40 shot down and three damaged with the use of 730 rounds of ammunition, then he flew back to base without suffering any damage. Capitano Camarda claimed a damaged Hurricane with the use of 80 rounds.
Part of the 17^o Gruppo formation was able to reach the Commonwealth Squadrons after a long chase at around 09:15 at the height of 6000 metres. They were Capitano Nioi, Sergente Maggiore Alvise Andrich (80^a Squadriglia), Tenente Emilio Marchi (80^a Squadriglia) and Tenente Renato Talamini (80^a Squadriglia). One P-40 each was credited to Capitano Nioi and Sergente Maggiore while three more P-40s were damaged; claimed by Capitano Nioi, Tenente Emilio Marchi and Tenente Giovanni Ghiglia (80^a Squadriglia). Tenente Saladini force landed with engine trouble. The pilots of 17^o Gruppo had expended 1330 rounds.
The raid had been performed by the usual formation of twelve Bostons escorted by nine Kittyhawks of 94 Squadron (take off 08:20 and landing 09:50), Tomahawks IIb of 2 SAAF and 4 SAAF Squadrons and finally by five Kittyhawk of 260 Squadron (take off 08:35 and landing 10:10) as extra top cover. 4 SAAF Squadron joined the formation over El Adem. In the meantime, twelve Hurricanes of 274 Squadron (take off 08:55) made a delousing sweep over Gazala together with 33 Squadron.
94 Squadron was attacked during the return journey by Bf 109s and MC.202s (possibly the two machines of the 6^o Gruppo). At 09:20, Pilot Officer G. L. Usher (Kittyhawk Ia AK741) and his wingman Sergeant W. T. Wallace discovered two Bf 109s and a Macchi over Martuba, while the bombers had just banked to return to base. Axis fighters had just taken off; in fact, they were 2,000 feet under the 94 Squadron that was flying at 18000 feet. Pilot Officer Usher recorded in his CFR:

“As the bombers turned to the left after dropping their bombs, I saw three E/A below on my left. I attacked straggling 109, which tried to avoid me by turning. I saw my bullets go into his left wing. This attack developed into dead astern and by time I was 30 yards behind him most of my guns had stopped firing. I noticed holes in his left wing and broke away in a dive to get under the bombers.
Ammunition expended 1100 rounds.”

At 09:20 on 13 April, ten MC.202 of the 17^o Gruppo (four from the 71^a Squadriglia, three from the 72^a Squadriglia and three from the 80^a Squadriglia), led by Maggiore Domenico Sciaudone (CO of the Gruppo), took off for a free sweep in the Bir Tengeder - Bir Abesc - Ain el Gazala area and to indirectly escort a SM.82 attacking a British LG. After around 45 minutes of flight, south of Gazala at the height of 4,000 m., they discovered a formation of around 25 enemy fighters that was immediately attacked. Two P-40s were claimed shot down by Capitano Pericle Baruffi (71^a Squadriglia) and Maresciallo Achille Martina (71^a Squadriglia), four more were claimed damaged by Capitano Nioi (two), Sergente Maggiore Aldo Bersani and Sergente Maggiore Mario Host (all from the 80^a Squadriglia). Capitano Baruffi’s MC.202 MM7895 was hit in the cooling system and he was obliged to force land close to Tmimi. Italian pilots landed at 10:30 after having expended 2800 rounds of ammunition.
Eleven Tomahawks of 2 SAAF had scrambled and intercepted 14 MC.202s. A dogfight followed but the action was inconclusive. Wing Commander Tristram Beresford CO of 233 Wing, leading the formation noted that the Italians, flying on the MC.202s, “put up a sensational exhibition of aerobatics, very careful to remain out of range ”. Despite this Lieutenat David Paddon claimed one damaged; presumably Baruffi. The Tomahawks landed back at 11:40. Wing Commander Beresford crash-landed at El Adem for an unspecified reason.
This was the first time the pilots of 2 SAAF were able to identify the Macchi MC.202. It is not possible to exclude the presence of a second Commonwealth unit considering that the returning Italian pilots claimed they had met 25 enemy fighters.

Between 15:50-17:50 on 4 June, nine CR.42s of the 50^o Stormo; five from the 388^a Squadriglia and four from the 390^a Squadriglia, 159^o Gruppo (Capitano Cerutti, (CO of the 158^o Gruppo), Baino, Sandroni, D’Alanno, Sergente Maggiore Pietro Bartolozzi, Tenente Piero Vodret, Ferraro, Rigetti and Sergente Maggiore Francesco Marcati) took off from Derna El Ftheiah and attacked enemy armoured and motorized forces in the immediate vicinity of Bir Hacheim.
Nine MC.202s from the 17^o Gruppo (four from the 72^a Squadriglia and five from the 80^a Squadriglia) provided the cover (16:00-17:25) and were led by Capitano Nioi. Once the bombs had been dropped and the strafing completed at 17:05, the Fiats of the 388^a Squadriglia that were coming out of the dive were attacked by enemy fighters. Six Spitfires and eight P-40s were seen (exactly the number of the counterpart). Sergente Maggiore Francesco Marcati (390^a Squadriglia, MM8527) and Sergente Maggiore Pietro Bartolozzi (388^a Squadriglia, MM5059) were shot down; the former did not bale out and lost his life, but the latter baled safely and was taken prisoner. Another two were hit by anti-aircraft fire. The 17^o Gruppo in their turn intervened to protect the CR.42s and the pilots of the 72^a Squadriglia returned claiming damaged to three enemy aircraft (250 rounds) while Capitano Nioi (80^a Squadriglia, 150 rounds) and Maresciallo Bruno Castellani (80^a Squadriglia, 60 rounds) fired at three aircraft, observing hits on one of them (credited as a shared damaged). Additional MC.202s of 96^a Squadriglia were present in the area on a free sweep (16:10-17:45) but they seem not have run into the enemy.
The whole of 233 Wing scrambled for another Stuka party over Bir Hacheim between 17:20-18:40. Six Kittyhawks of 260 Squadron clashed with four CR.42s protected by six Bf l09s or Macchi MC.202s and claimed one CR.42 (Flying Officer John Waddy in AL198).
Eight Tomahawks of 5 SAAF Squadron came across six CR.42s and two Bf l09s at 18:00.

“Capt. Botha [AN448/GL-H] was after a CR.42 when he was forced to avoid four of own AC all filling the atmosphere with lead. The CR 42 did a slow roll off the top of the four and Capt. Botha shot him down in flames.”

“…Met up with 3+ CR.42s which jettisoned their bombs. At least 5 of us fired at one of these. I was last to fire and saw it go down afterwards. In own opinion, I must have killed the pilot. I was rather discouraged by others when I said that, so I made no claim”

On 10 June, the 6^o Gruppo and the 17^o Gruppo jointly carried out a free sweep in the Bir Hacheim - Bir el Harmat area.
Between 14:50 and 14:55 six planes of the 6^o Gruppo drawn two each from the three Squadriglie had taken off under Capitano Domenico Camarda (79^a Squadriglia). At 15:00 they were followed by six planes of the 17^o Gruppo (four from the 72^a Squadriglia and two from the 80^a Squadriglia) led by Capitano Clizio Nioi (CO 80^a Squadriglia).
At 15:20, while flying at 5000 metres east of Bir Hacheim, a mixed formation of Hurricanes and P-40s was attacked. According with the 6^o Gruppo the enemies were around twenty while according with the 17^o Gruppo they were fifteen.
Six P-40s were claimed by the pilots of the 6^o Gruppo and one probable with 14 more damaged with the use of 2625 rounds of ammunition. Credit for the victories went to Capitano Camarda (who also fired on five more fighters; 500 rounds, Sergente Amedeo Benati (79^a Squadriglia), Sergente Maggiore Luigi Morosi (81^a Squadriglia) (plus one probable), Maresciallo GianLino Baschirotto (88^a Squadriglia) (two destroyed) and Sergente Maggiore Anano Borreo (88^a Squadriglia).
Only four pilots of the 17^o Gruppo were able to join the combat. Sergente Maggiore Alvise Andrich (80^a Squadriglia) claimed a P-40, while a second was shared among Capitano Nioi, Tenente Giovanni Ghiglia (80^a Squadriglia) and Sergente Maggiore Aldo Bersani (80^a Squadriglia); the four pilots had used 1760 rounds of ammunition.
The running fight lasted for a long time and went as far as El Adem. All the Italian pilots came back unscathed, the 6^o Gruppo between 16:00 and 16:05 while the 17^o Gruppo returned at 16:20.
It seems that the 1^o Stormo’s pilots had met a mixed formation of 73 Squadron and 213 Squadron. At 15:40, some Hurricane IIcs of 73 Squadron, (possibly twelve), covered by eleven Hurricane II from 213 Squadron (that had taken off at 15:35), had taken off for a protective cruise over Bir Hacheim.
At 16:20 and south-west of El Adem at a height between 8000 and 11000 feet, the pilots of 73 Squadron reported being jumped by a formation of twelve Bf 109 and Macchi MC.202 despite the escort of 213 Squadron. They claimed to have probably shot down one of the attackers (Sergeant Ronald Baker in Hurricane BN402 claimed a probable Bf 109F) and to have damaged two more (Squadron Leader Derek Ward in Hurricane BN131/P and Sergeant L. T. Henry in BE372/H) while losing the Hurricane II BE568 of Sergeant Alan Stuart Wilson, who jumped with parachute but without suffering any additional loss.
213 Squadron reported being attacked by four Bf 109s (possibly the Macchis of the 17^o Gruppo) and claimed three of them damaged (Pilot Officer W. H. Thomlinson in BM981/AK-G, Warrant Officer R. J. Wallace in BN139/AK-U and Pilot Officer P. P. Wilson in BM983/AK-C) 10 miles south-west of Knightsbridge. One Hurricane was damaged (Sergeant Menzies whose BN353/AK-D was hit in cockpit and oil cooler). 73 Squadron was back at 17:00.

As of 8 November 1942 (on the launch of Operation Torch in North Africa), Capitano Nioi served as CO of the 80^a Squadriglia, 17^o Gruppo CT. The unit was based at Decimomannu, Sardinia, and equipped with MC.202s.

In 1943, Nioi still served in the 17^o Gruppo Autonomo.

Nioi ended the war with 1 biplane victory and a total of 7.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
1	23/06/40	18:40-	1	’Potez 63’ (a)	Destroyed	Fiat CR.32		Capo Gallo	80a Squadriglia
	1941
?	12/12/41	16:00-16:35	1	Tomahawk (b)	Destroyed	MC.202		Gazala area	80a Squadriglia
	12/12/41	16:00-16:35	1	Tomahawk (b)	Probably Destroyed	MC.202		Gazala area	80a Squadriglia
	1942
?	28/03/42	13:35-	1	P-40 (c)	Destroyed	MC.202		W Tobruk	80a Squadriglia
	28/03/42	13:35-	1	Boston (c)	Damaged	MC.202		W Tobruk	80a Squadriglia
5	03/04/42	10:30-11:20	1	P-40 (d)	Destroyed	MC.202		Derna	80a Squadriglia
	03/04/42	10:30-11:20	1	P-40 (d)	Probable destroyed	MC.202		Derna	80a Squadriglia
6	06/04/42	08:20-09:40	1	P-40 (e)	Destroyed	MC.202		Ain el Gazala	80a Squadriglia
	06/04/42	08:20-09:40	1	P-40 (e)	Damaged	MC.202		Ain el Gazala	80a Squadriglia
	13/04/42	09:20-10:30	1	P-40 (f)	Damaged	MC.202		S Ain el Gazala	80a Squadriglia
	13/04/42	09:20-10:30	1	P-40 (f)	Damaged	MC.202		S Ain el Gazala	80a Squadriglia
	04/06/42	17:05-17:25	1/2	P-40 (g)	Shared damaged	MC.202		Bir Hacheim	80a Squadriglia
	10/06/42	15:20	1/3	Hurricane (h)	Shared destroyed	MC.202		Bir Hacheim - Bir el Harmat	80a Squadriglia

Biplane victories: 1 destroyed.
TOTAL: 7 and 1 shared destroyed, 2 probably destroyed, 4 and 1 shared damaged.
(a) Probably claimed in combat with five LeO 451s from GB II/11, which lost one aircraft (n^o 144) in a forced landing were the crew was KIA.
(b) Claimed in combat with P-40s from 2 SAAF, 4 SAAF, 3 RAAF and 112 Squadrons, which claimed 6 and 5 damaged while losing 7 and 3 damaged P-40s. Axis fighters claimed 15, 2 probables and 2 damaged while losing 2 and 2 damaged fighters.
(c) Claimed in combat with P-40s from 2 SAAF, 94 and 450 Squadrons and Bostons from 12 SAAF Squadron. 4 Bostons were damaged. The Allied fighters claimed 1 destroyed, 2 probables and 1 damaged while suffering 1 destroyed and four damaged P-40s (one pilot DoW). Axis fighters claimed 3 P-40s destroyed, 2 probables and 1 damaged and 1 damaged Boston while losing 1 Bf 109F and 1 MC.200 (pilot KIA).
(d) Claimed in combat with P-40s from 2 SAAF, 4 SAAF, 94, 260 and 450 Squadrons and Hurricanes from 274 Squadron. The Allied fighters claimed 3 destroyed, 4 probables, 3 damaged for the loss of 3 aircraft (1 pilot KIA) and three damaged. Axis fighter from the 1^o Stormo and JG 27 claimed 9 destroyed, 2 probables and 2 damaged for the loss of 3 fighters (2 pilots KIA).
(e) In this confusing combat it seems that Allied fighters claimed 3 destroyed, 1 probable and 6 damaged while losing 2 and getting 2 damaged. Axis fighters claimed 7 destroyed, 1 probable and 7 damaged while getting 1 aircraft damaged.
(f) Claimed in combat with 2 SAAF Squadron, which claimed 1 damaged without losses. The 17^o Gruppo claimed 2 destroyed and 4 damaged while losing 1 MC.202 (pilot safe).
(g) Claimed in combat with P-40s from 2, 4 and 5 SAAF Squadron, which didn’t claim any fighters and didn’t lose anything. The 17^o Gruppo claimed 4 fighters damaged without losses.
(h) Claimed in combat with RAF fighters from 73 and 213 Squadron which claimed 1 probable, 5 damaged while suffering 1 Hurricane shot down (73 Squadron) and 1 damaged (213 Squadron). 1^o Stormo claimed 8 Hurricanes, 1 probable and 14 damaged without losses.

Sources:
3^o Stormo, storia fotografica - Dai biplani agli aviogetti - Carlo Lucchini and Leproni Enrico, 1990 Gino Rossato Editore
A History of the Mediterranean Air War 1940-1945: Volume One – Christopher Shores and Giovanni Massimello with Russell Guest, 2012 Grub Street, London, ISBN 978-1908117076
A History of the Mediterranean Air War 1940-1945: Volume Two – Christopher Shores and Giovanni Massimello with Russell Guest, Frank Olynyk & Winfried Bock, 2012 Grub Street, London, ISBN-13: 9781909166127
A History of the Mediterranean Air War 1940-1945: Volume Three – Christopher Shores and Giovanni Massimello with Russell Guest, Frank Olynyk & Winfried Bock, 2016 Grub Street, London, ISBN-13: 9781910690000
Ali d'Africa - Michele Palermo and Ludovico Slongo, 2009 IBN Editore, ISBN 88-7565-060-8
Annuario Ufficiale Delle Forze Armate Del Regno D’Italia Anno 1943. Part III Regia Aeronautica – 1943 Istituto Poligrafico Dello Stato, Roma
Assi Italiani Della Caccia 1936-1945 - 1999 Aerofan no. 69 apr.-giu. 1999
Diario Storico 153^a Squadriglia anno 1940.
Diario Storico 154^a Squadriglia anno 1940.
Eagles over Gazala: Air Battles in North Africa May-June 1942 – Michele Palermo, IBN Editore, ISBN (10) 88-7565-168-X
Elenco Nominativo dei Militari dell’ A. M. Decorati al V. M. Durante it Periodo 1929 - 1945 2 Volume M - Z
La Battaglie Aeree In Africa Settentrionale: Novembre-Dicembre 1941 – Michele Palermo, IBN, ISBN 88-7565-102-7
Malta: The Hurricane Years 1940-41 - Christopher Shores and Brian Cull with Nicola Malizia, 1987 Grub Street, London, ISBN 0-89747-207-1
Additional information kindly provided by Michele Palermo and Ludovico Slongo.