Mario Balotelli scored twice to move Nice seven points clear of Ligue 1 champions Paris Saint-Germain after beating 10-man Dijon 2-1 at the Allianz Riviera.
Lucien Favre's men extended their advantage at the top of the table to four points over Monaco, albeit they can restore the gap to one by beating Caen later on Sunday, after a battling performance with Balotelli making it eight goals in as many league appearances this season.
Balotelli, who posed in a Santa hat after the match, scored his first from the penalty spot in the 32nd minute after strike partner Alassane Plea had been fouled by Yunis Abdelhamid.
Dijon levelled with a penalty of their own from Julio Tavares five minutes later, with Arnaud Souquet conceding the spot-kick for fouling Vincent Rufli.
Balotelli's winner came on 50 minutes, the ex-Liverpool striker converting Souquet's low cross from close range despite appearing to have been in an offside position.
Visitors Dijon, now third from bottom with only three wins from 18 league games, saw their hopes of a comeback ended when Cedric Varrault saw red for a foul on Balotelli in the closing stages.
Second-placed Monaco can move to within four points of Nice if they can secure victory over Lyon later on Sunday, with PSG sitting third after their shock loss to Guingamp.