[3] After working as a schoolmaster Nicholson made his first professional stage appearance in Cork on 26 December 1896 in Frank Benson's company.
[1] Nicholson's Shakespearean roles included Fabian, Starveling, Casca, Dogberry, Polonius, Shallow, and Old Adam.
[6] His other parts included the Centurion in Androcles and the Lion (1913), Sir Oliver Surface in The School for Scandal (1919), Old Hardcastle in She Stoops to Conquer (1922), Dr Chasuble in The Importance of Being Earnest (1923) and Brovik in The Master Builder (1932).
He appeared in variety programmes, documentaries and plays; his roles in the last included the Old Shepherd in The Winter's Tale, Junius Brutus in Coriolanus, Firs in The Cherry Orchard, Starveling in A Midsummer Night's Dream and parts in plays by Maurice Maeterlinck and Arthur Schnitzler.
[7] He is credited by Who's Who in the Theatre with having coined the name Walter Plinge as a stage pseudonym used when it would be undesirable or impossible for an actor to appear under his real name.