Nicholetts was appointed Officer Commanding No. 228 Squadron, just after the outbreak of the Second World War. Based at Alexandria, Egypt, flying a Short Sunderland, Nicholetts personally commanded the RAF reconnaissance flight preceding the November 1940 Fleet Air Arm Taranto raid. He went on to be Station Commander at RAF Haifa and then RAF Shallufa, before later being taken prisoner of war by the Japanese in 1942 in the Dutch East Indies. After the war he became Senior Air Service Officer at Headquarters No. 25 (Armament) Group and then Air Officer Commanding the Central Photographic Establishment before becoming Director of Organisation at the Air Ministry in 1948. He was then made Senior Air Service Officer at Headquarters RAF Coastal Command in 1951, Air Officer Commanding No. 21 Group in 1953 and Air Officer Commanding AHQ Malta in 1956. His last appointment was as Inspector-General of the RAF in 1958 before retiring in 1959.