He went on to become Chairman of Council of South Wales Football Association between 1920–1921 and was a Director of Cardiff City when they reached the F.A. Cup final in 1927. He was influential in critical team decisions in the run up to the cup final and almost removed the Cardiff Captain, Fred Keenor, in the run up to the match. "Keenor was officially listed at a meeting of club directors at The Corporation pub in Canton on 19 January 1927. At the summit, called by Sid Nicholls, fellow board member Walter Riden – Keenor's old teacher at Stacey Road Primary School in Adamsdown – proposed listing the captain. Nicholls seconded the idea and Keenor's future at Ninian was in jeopardy. But within weeks the captain won his place back, his name was removed from the list and on 23 April he led the Bluebirds to their most famous victory, a 1–0 win over Arsenal.". Nicholls is seen in film newsreels of the match introducing King George V to the Cardiff City players and sat with the King to watch the match. By June 1928 Nicholls was the Vice-President F. A. Wales.