 He worked as a surveyor and as chairman of a paint company, serving as President of the Wallpaper and Paint Retailers' Association.He was a Lloyd's of London underwriter, a company director and chairman of Radio Luxembourg Ltd.

Nicholls was Member of Parliament for Peterborough from 1950 to 1974, when he lost in the October election of that year to Labour's Michael Ward, having held on by just 22 votes in the election eight months earlier.This was the second close call during his time as MP for Peterborough – in 1966, he held his seat by just three votes.