Nicholas was a high profile criminal barrister who in January 2015 became the Recorder of London, which is the most senior legal post at the Old Bailey. Before that he was the 80th Common Serjeant of London; a post he had held since May 2013. In 2007 Nicholas was involved in the inquest into the death of Diana, Princess of Wales and in 2008 led the Prosecution against the murderers of Ben Kinsella.

A Liveryman of the Worshipful Company of Feltmakers, Judge Hilliard is also a Trustee of Crisis, the charity for single homeless people, and the Ben Kinsella Trust, which aims to promote awareness of the effects of knife crime.