Nemec took a backhand pass from Jack Hughes and chipped the puck past Calgary goalie Devin Cooley, who went for the poke check.
Dawson Mercer also scored for the Devils (25-22-2), who bounced back from a 4-1 loss at home to the Carolina Hurricanes on Saturday. Jacob Markstrom made 21 saves.
Nazem Kadri scored for the Flames (21-24-4), who had won two straight. Cooley made 29 saves.
After a scoreless first period, Cooley denied Connor Brown on a short-handed breakaway at 5:47 of the second period by getting his glove on the New Jersey forward’s wrist shot to send the puck out of play.
Mercer was able to give the Devils a 1-0 lead at 7:51 of the second. Situated at the right post, Mercer redirected a pass from defenseman Dougie Hamilton that hit Cooley’s arm before trickling across the goal line.
Kadri tied it 1-1 at 9:44 with his first goal in 14 games. He dropped the puck back on a rush to a trailing Kevin Bahl, who then sent a return pass to Kadri for a one-timer in the right circle that beat Markstrom, who was screened by Connor Zary.
Defenseman Zach Whitecloud made his debut with the Flames after being acquired in a trade with the Vegas Golden Knights on Sunday for defenseman Rasmus Andersson. Whitecloud had two shots on goal in 22:33 of ice time.
New Jersey defenseman Luke Hughes left the game midway through the the second period.
