Neymar, Angel Di Maria and Edinson Cavani - 350 million euros worth of talent - were all ruled out through injury. Kylian Mbappé was kept away from the tussle with the Coupe de France final in mind.
Skipper Thiago Silva and Thomas Meunier were among the wounded from the defence. But it was one of their number who opened the scoring in the 19th minute.
Dani Alves claimed his first league goal of the season with a classy strike past the Nantes goalkeeper Maxime Dupe.
Nantes levelled within three minutes. Valentin Rongier swung in a corner from the left and Diego Carlos powered his header past Gigi Buffon.
And to the joy of the home faithful, they edged ahead just before half-time. Abdul Majeed Waris slotted in his fifth goal of the season on his 100th top flight appearance.
Alves then put through his own net seven minutes into the second-half to increase the hosts' advantage.
And though 20-year-old Metehan Guclu scored on his Ligue 1 debut to reduce the deficit, the visitors could not conjure up an equaliser in stoppage time as they slumped to their second consecutive league defeat.
The win took Nantes up to 14th, 12 points clear of the relegation zone with six of their 38 games remaining.
PSG have also played 32 matches and will be champions without kicking a ball if Lille fail to claim all three points at Toulouse on Sunday afternoon.
Should Lille win, PSG will hoist their fifth title in six years with victory over Monaco at the Parc des Princes on Sunday evening.