His grandfather, Tom Nickalls, was one of the founding members of London Rowing Club.
In 1920, rowing for Magdalen, Nickalls partnered Richard Lucas to win the Silver Goblets & Nickalls' Challenge Cup at Henley Royal Regatta, beating Bruce Logan and S I Fairbairn in the final.
Later in the year, Nickalls was a member of the Leander eight which won the silver medal for Great Britain rowing at the 1920 Summer Olympics, coming within half a length of winning.
In 1922, he rowed in the losing Oxford Boat Race crew again, but regained Silver Goblets with Lucas, beating Karl Vernon and H West in the final.
Nickalls said afterwards: "We stood on each other's foot when it was our turn to interrupt and simply poured excited words from start to finish, totally oblivious to being heard or not."