Nunan was educated at St Patrick's College, Ballarat where he was a champion school athlete and played football in the school first eighteen team in 1923.
Nunan was granted a permit to play with Footscray in late May 1925 after playing with the Footscray reserves.
Nunan played with Footscray reserves in 1928, then played with Essendon reserves in 1929 1930, and 1931.
In April 1932, Nunan was cleared from Essendon to North Melbourne where he played VFL reserves football.
↑Holmesby, Russell; Main, Jim (2014). The Encyclopedia of AFL Footballers: every AFL/VFL player since 1897 (10thed.). Seaford, Victoria: BAS Publishing. p.662. ISBN978-1-921496-32-5.
↑"1928 - THE JUNIOR PLAYERS". The Herald (Melbourne, Vic.: 1861 - 1954). 4 May 1928. p.12. Retrieved 21 March 2026.
↑"1929 - CLOSE WIN BY ESSENDON SECOND EIGHTEEN". The Essendon Gazette and Flemington Spectator, Keilor, Bulla and Broadmeadows Reporter (Moonee Ponds, Vic.: 1924 - 1946). 20 June 1929. p.10. Retrieved 21 March 2026.
↑"1930 - SECOND EIGHTEENS". The Age (Melbourne, Vic.: 1854 - 1954). 21 July 1930. p.6. Retrieved 22 March 2026.
↑"1931 - ESSENDON SECONDS". The Essendon Gazette and Flemington Spectator, Keilor, Bulla and Broadmeadows Reporter (Moonee Ponds, Vic.: 1924 - 1946). 23 April 1931. p.2. Retrieved 22 March 2026.