PSG goalkeeper Alfonso Areola made the first save after a shot from Sada Thioub in the opening eight minutes of a hotly contested battle.
Given their amazing start to the season, the French champions were certain to extend their fine run but their earlier struggles against the new boys seemed to suggest otherwise.
After managing to sustain the earlier onslaught, the visitors raced into the lead after Neymar completed a brilliant build-up with a fine finish on 34 minutes.
It took six minutes to add a second and Angel Di Maria scored directly from the corner flag.
A minute to halftime, Areola made a sterling finger-tip save from dangerman Thioub following a slow build-up play.
PSG were struggling to maintain the rash challenges poured in from the home side, with Neymar suffering the most.
The chance to go further came on 59 minutes when Kylian Mbappe’s goal-bound effort produced Bernardoni to save for a corner.
Nimes pulled a goal back at the midway point through the boot of Antonin Bobichon after PSG went to sleep at the back.
PSG made their first change of the game, takin off Stanley Nsoki for Kehrer Thilo after 67 minutes of play.
Nimes were awarded a penalty and a chance to draw level and Teji Savanier made no mistake to send Alfonso the wrong way on 71 minutes.
That put a spring in their step as Sofiane Alakouch rattled the crossbar minutes later from just outside the box with Alfonso well beaten.
The champions made the game safe though on 77 minutes when Kylian Mbappe fired home a world class with Edison Cavani adding a fourth in added time to round off the victory.
Both sides also ended the game with 10 men as Savanier was sent off for bad challenge on Mbappe, who was given his marching order for retaliating.