Born at Fort George, Scotland, he was the eldest son of B. W. Hewittson Nicholson of the army medical staff.
After a boyhood passed at Gibraltar, Malta, and the Cape, where his father was stationed, he studied medicine at the University of Edinburgh in 1841.
[1] Nicholson contributed genealogical tables of Xhosa chiefs to a Compendium of Kafir Laws and Customs printed by the government of British Kaffraria at Mount Coke in 1858.
[1] In 1875 Nicholson edited, for the then recently formed New Shakspere Society, the First Folio and the first quarto of Henry the Fifth, and began the preparation of the "Parallel Texts" of the same play, issued in 1877 (not completed because serious illness).
[1] Encouraged by William Tennant Gairdner, Nicholson brought out in 1886 a reprint of Reginald Scot's Discoverie of Witchcraft (1584).