The defender who joined the Eaglets in July from Kortrijk was on hand to help Patrick Vieira’s men extend their winning run to four.
Bernard Blaquart’s men started the game on an uninspiring note after Faitout Maouassa got his second booking in the 21st minute and was subsequently sent off.
The Crocodiles lost another man in the 45th minute when Loick Landre was expelled for a serious foul play.
Their visitors capitalised on their numerical strength in the 61st minute with Atal scoring the solitary goal that made the difference in the tie.
The young defender featured for the entire duration of the contest as Nice increased their points to 20 in 13 matches to be placed sixth in the log.
Atal will hope to continue the impressive form when his side host Lille at Allianz Riviera on November 25.