[1] In 1998 Nicholson was appointed assistant organist at St Mary's Episcopal Cathedral, Edinburgh.
He left that position to become organist and director of music at Waltham Abbey Church.
[1] In 2006 he was appointed Assistant Director of Music of St Philip's Cathedral, Birmingham.
[3] In 2010 he was appointed organist and master of choristers at St Patrick's Cathedral, Dublin, a post he still maintains as of 2024.
[1][4] As a soloist and accompanist, Stuart has performed in major venues like the Barbican Centre, Royal Albert Hall, Symphony Hall, Birmingham, Westminster Abbey and York Minster.