The champions suffered a shock 3-2 loss to lowly Lorient on Sunday - their first defeat under Mauricio Pochettino - but responded with a comfortable victory on home soil.
Star man Angel Di Maria profited from a terrible Lamine Fomba error to open the scoring and then crossed for Pablo Sarabia to add a second before half-time.
Kylian Mbappe scored a stunning third goal for PSG, who were without the suspended Neymar, but they remain third in the table as leaders Lille and second-place Lyon also triumphed.
Moise Kean clipped the outside of the post with a header from 10 yards but PSG were ahead seven minutes later through Di Maria's composed finish.
Nimes midfielder Fomba played the ball straight to Di Maria's feet and the Argentina international fired away from Baptiste Reynet after teeing himself up.
The home side nearly had a second soon after when Presnel Kimpembe headed a corner back across goal and Thilo Kehrer turned it against the underside of the crossbar.
But Sarabia did manage to double his team's tally nine minutes before the interval, heading Di Maria's right-sided cross into the bottom-right corner from five yards.
Fomba was denied by Sergio Rico as he tried to make amends for his earlier error, while Anthony Briancon and Renaud Ripart also had attempts saved by the stand-in PSG keeper.
Nimes continued to ask questions of their opponents but the game was put out of their reach by Mbappe, who curled a shot past a stranded Reynet to seal the win.