Nicholson studied at Herkomer’s school at Bushey (1888-89), where he met James Pryde, who was to become his brother-in-law, and at the Académie Julian in Paris, 1889-90. He and Pryde formed a partnership in the 1890s, calling themselves ‘J. & W. Beggarstaff’, designing posters and graphic works. Nicholson had a series of coloured woodcuts (The Alphabet, Queen Victoria and London Types) published by Heinemann, 1896 to 1900. He also designed sets for theatre productions, including the original production of Peter Pan in 1904, and illustrated several books.
Subsequently Nicholson had great success as a portrait painter, and was a founder-member of the National Portrait Society in 1911. He was equally successful as a painter of still-lives and landscapes. Nicholson was a Trustee of the Tate Gallery from 1934 to 1939, and was knighted in 1936.