The 120-times capped Bonucci was part of Italy’s Euro 2020-winning team and is a nine-time Serie A champion.
Chelsea have progressed to the quarter-finals of the UEFA Champions League following a 2-0 win over Bundesliga side Borussia Dortmund.
“Nottingham Forest is delighted to confirm the signing of striker Emmanuel Dennis from Watford,” a club statement said.
Palace look like having one of the toughest starts of any club as after the Gunners, they go to Anfield, host Aston Villa and then head to Manchester City.
“They have a very clear identity, a clear idea of how they want to play,” he said.