Tempers boiled over at the City Ground after Wolves lost on penalties and former Molineux man Morgan Gibbs-White celebrated in front of the travelling fans.
Gibbs-White slid on his knees in front of the away end, prompting Wolves players to confront the Stafford-born midfielder. The 22-year-old had earlier goaded Wolves fans after scoring from the spot during the penalty shoot-out, which Wolves lost 4-3.
A fracas ensued after the final whistle with players having to be separated.
Wolves have now been fined £45,000 by the FA and Nottingham Forest £40,000.
A statement said: “Both clubs admitted failing to ensure that their players and benches conducted themselves in an orderly fashion and refrained from provocative behaviour after the final whistle.
“Nottingham Forest FC and Wolverhampton Wanderers FC’s fines were imposed by an independent Regulatory Commission, and its written reasons for them will be published in due course.”
Wolves defender Toti Gomes said afterwards that Gibbs-White wanted to fight him, but added: “It calmed down and we’re all friends again.”