Nicholson was appointed as Chief Commissioner in 1922 at the age of 59 having spent most of his 39 years of service with the police in regional and rural Victoria, in particular the Ballarat area. At the time he was both the oldest and most senior officer in the force. Police historian Robert Haldane wrote "[Nicholson's] affinity with the Ballarat District over many years and his close association with the then Chief Secretary and Minister of Public Health, the sitting member for Ballarat West, Major Matthew Baird, led to suggestions that Nicholson received undue favour in being appointed Chief Commissioner."
