Carl Hagelin also scored and Henrik Lundqvist had 29 saves as the Rangers won their second game in two nights after a three-game losing streak. New York moved into a tie for eighth place in the Eastern Conference, the cutoff point for the playoffs.
Travis Zajac and Anton Volchenkov scored for New Jersey, which lost its third in a row (0-2-1) and slipped into a tie with New York, which has a game in hand.
Devils goalie Martin Brodeur was on the bench for the first time in a month and is expected to play Thursday. New Jersey
By Rangers-Devils standards, this game was wide open and had its share of miscues and great saves by Lundqvist and Johan Hedberg, who started all 13 games since Brodeur sustained a pinched nerve in his back.
Nash's game winner might have been one of the mistakes by Hedberg, who helped set up Del Zotto's third goal of the season by playing the puck near his bench on a power play.
Nash's team-high 10th goal came on a counterattack shortly after a penalty to Rangers defenseman Anton Stralman ended. Del Zotto found Nash on the right wing, and the big forward skated into the Devils zone and beat Hedberg with a shot from the right circle at 7:25 of the second period to make it 3-2.
The Rangers, who hadn't scored two goals in regulation in their last four games, scored twice in the first period but the Devils tied it on goals by slumping players.
Shortly after Kovalchuk banged a power-play shot off the post, Del Zotto swatted a shoulder-high pass from the corner by Derek Stepan into the net at 11:49 for New York's third short-handed goal of the season.
The Devils' second power play was more productive, and a little bit luckier at 15:15. A shot from the point by Peter Harrold was partially blocked. Del Zotto tried to kick the puck to the corner, but it went to Zajac's stick in the right circle for his first goal in 11 games.
New York took the lead again less than two minutes later on Hagelin's eighth goal.
It also was a little lucky.
Dan Girardi's shot from the right point was wide of the net but it bounced off the end boards right to Hagelin on the left doorstep for a stuff-in.
Volchenkov tied it 2-2 just 23 seconds later with a shot from the left point that found its way past about five players and Lundqvist. It was the Russian's first goal in 36 games, dating to last season, and his 19th goal in a decade in the NHL.
NOTES: Del Zotto's goal was his 100th NHL point. ... Defensemen Stu Bickel and Matt Gilroy were healthy scratches for the Rangers. ... Devils C Andrei Loktionov (undisclosed injury) hopes to be back in the lineup in Carolina on Thursday. ... Devils D Marek Zidlicky played in his 600th NHL game.