Christophe Galtier's men took the lead after 24 minutes as Benjamin Corgnet's deflected strike left Nantes goalkeeper Remy Riou stranded.
And the victory was completed seven minutes from time, Mevlut Erding converting from the spot after Chaker Alhadhur was adjudged to have handled in the area.
Reims continued their recent good form with a 4-1 victory over struggling Ajaccio.
Former Montpellier striker Gaetan Charbonnier put the hosts in command with a goal either side of the hour mark, before winger Eliran Atar extended the lead with his second goal of the season.
Ajaccio did pull one back through experienced forward Eduardo shortly after, but the game was put beyond all doubt when Floyd Ayite netted 13 minutes from time to make it four league games without defeat for Reims.
The result was another blow to Ajaccio's survival hopes and the Corsicans will now head into the mid-season break at the foot of the table due to Sochaux's 2-1 win against Rennes.
Striker Cedric Bakambu opened the scoring from the spot for Herve Renard's Sochaux after 18 minutes, only for Romain Alessandrini to level things up for Rennes with a penalty of his own just before the interval.
But it was Bakambu who had the final say midway through the second half as he struck again to move Sochaux off the bottom with their first win in 11 league games.
Nice came from behind to beat Evian 3-1 and earn their second successive win.
Defender Cedric Mongongu put Evian in front from the spot, however, a double from winger Eric Bautheac and a late Alexy Bosetti strike ensured the points for the hosts.
Meanwhile, the games between Bastia and Montpellier and Toulouse and Guingamp both ended goalless.
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