Bradley Barcola's stylish finish just before the break gave PSG the lead, but a Mostafa Mohamed header in the second half made it look as if the points would be shared in the capital.
However, Kolo Muani pounced in the six-yard box seven minutes from time to allow PSG to open up a six-point lead at the top of the table.
"I think that before an important match like Wednesday's (Borussia Dortmund), we were good right from the first minute. Nantes defended well and it was a match that allowed us to strengthen our position in the league," said PSG coach Luis Enrique.
In Paris, a first half dominated by the hosts, though with few clear-cut chances at either end, was illuminated by Barcola in the 41st minute when he stroked home his first goal for PSG.
Playing a one-two on the left wing with Vitinha, the 21-year-old glided into the box before opening his body and bending the ball beyond Alban Lafont.
But Nantes were back on terms 10 minutes after the break when Florent Mollet's corner was nodded in by Mohamed at the near post, leaving last week's hero Arnau Tenas little chance.
PSG were handed a welcome boost when teenager Warren Zaire-Emery entered the fray after 61 minutes, though returning captain Marquinhos left the field at the same time. However, the key change came with 11 minutes remaining as goalscorer Barcola made way for Kolo Muani.
And just four minutes later, the French international was on hand to turn in a rebound from close-range and his fourth goal of the season was enough to give the home team a narrow 2-1 win.
Luis Enrique declared the result "a good preparation for a Champions League match" as his side now turn their attention to next week's do-or-die clash in Dortmund, the Parisians need a result to reach the knockout stages.
December 9, 2023