The striker successfully converted a penalty to give the Hornets the lead late in the first half at Vicarage Road, and made the gesture towards the visiting supporters situated behind the goal.
Deeney received no card from referee Mike Dean and after investigating the matter, the Football Association (FA) has decided to take no action.
"Watford's Troy Deeney will not face any formal action following his goal celebration during the game against Chelsea on Monday [05/02/18]," read an FA statement.
"Video footage was referred to a panel of three former elite match officials who were asked to consider independently whether it was a red card offence.
"The response was not unanimous, therefore, no disciplinary action will follow. Nevertheless, The FA will write to the player and warn him as to his future conduct."
Deeney has already been disciplined on two occasions this season after receiving a retrospective three-game ban for raising his hands to Joe Allen's face against Stoke City in October, while he was sent off for a poor challenge on Huddersfield Town's Colin Quaner in December, earning a four-game suspension.
The 29-year-old striker now has three goals and two assists in 17 appearances this season for Watford, who sit 11th in the Premier League table after Monday's win.
Meanwhile the loss heaped more misery on Chelsea, as it was their second straight heavy defeat to weaker opposition and placed more pressure on under-fire manager Antonio Conte.