The Belgian midfielder had one of his best games in a Spurs shirt to help turn around that deficit into a memorable 5-3 win at the Lane.
Nacer scored once and was involved in another three goals - striking the post to allow Danny Rose to convert for 2-1 and setting-up Harry Kane for 4-1 in the second half.
Diego Costa had put the Blues 1-0 up before Harry, Danny and Andros Townsend sent us into half-time 3-1 up. Harry made it 4-1, Eden Hazard reduced arrears but Nacer put the issue beyond doubt at 5-2, his sixth goal in the Premier League this term.
"It was amazing," said Nacer. "These are the best games to win, against the league leaders and we showed great football and a great attitude as well.
"We conceded the goal but we knew we were playing well and creating chances. We knew we could get back into the game. We kept doing our thing, played our football and did that.
"The fans were right behind us all the way and it’s fantastic to win at home against Chelsea."
As for his own form, Nacer added: "I’m working hard every game. I want to show the best of myself. I feel great and I’m just happy to help us win games. I just try to do my best and the most important thing is three points."