Brazilian striker Carlos Vinicius pounced in the last minute to move Monaco up to 16th place in the French league and keep Lille under pressure in the fight for second.
As so often this season, Nice played without a recognized center forward and midfielder Wylan Cyprien opened the scoring midway through the first half with a free kick from 30 meters (33 yards) out. Striker Firmin Mubele equalized in the 89th minute for Toulouse, which moved further away from the danger zone.
Meanwhile, runaway league leader Paris Saint-Germain remains 17 points clear of Lille despite playing two games less, and is even closer to another title after Lille’s stumble.
Marseille has found form since the arrival of striker Mario Balotelli from Nice. He has netted five times in seven games to help the club into fourth place.