His father was a stockjobber on the London Stock Exchange with a particular expertise in investing in American railroads.
Nickalls was educated at Magdalen College, Oxford and rowed with hs brother in the 1891 Boat Race.
He joined London Rowing Club and with his brother he won the Silver Goblets at Henley in 1894, 1895 and 1896.
His sister Florence Nickalls married William Adolf Baillie Grohman, an Anglo-Austrian author.
The family had connections and property in the United States, and in 1914 Nickalls went to America to coach at the University of Pennsylvania.