In the 1973–74 season, Nicholas played as a substitute (replacing Prop David Chisnall), and scored a try in Warrington's 27–16 victory over Rochdale Hornets in the 1973–74 Player's No.6 Trophy Final at Central Park, Wigan on Saturday 9 February 1974, and played left-second-row in Warrington's 24–9 victory over Featherstone Rovers in the 1974 Challenge Cup Final at Wembley Stadium, London on Saturday 11 May 1974, in front of a crowd of 77,400.
He played as a substitute (replacing right-second-row Thomas Martyn) in the 7–14 defeat by Widnes in the 1975 Challenge Cup Final at Wembley Stadium, London on Saturday 10 May 1975, in front of a crowd of 85,998.
Nicholas played right-prop, in the 9–4 victory over Widnes in the 1977–78 Players No.6 Trophy Final during the 1977–78 season at Knowsley Road, St. Helens on Saturday 28 January 1978, and played right-prop, in the 14–16 defeat by Widnes in the 1978–79 John Player Trophy Final during the 1978–79 season at Knowsley Road, St. Helens on Saturday 28 April 1979.
[5] Mike Nicholas was team manager of Wales at the 2000 Rugby League World Cup.
Nicholas was appointed Member of the Order of the British Empire (MBE) in the 2020 New Year Honours for services to rugby league in Wales.