Timothee Kolodziejczak put through his own net in the 52nd minute, giving PSG a seventh-successive victory in Le Championnat - a new benchmark for the side
Laurent Blanc's men were handed a huge boost ahead of the midweek quarter-final first leg as Thiago Silva played the full 90 minutes despite suffering a fractured cheekbone last week - although the Brazil international produced an unconvincing performance at the Allianz Riviera.
Yet the league leaders were still able to claim all three points and move 13 clear of Monaco ahead of their trip to Evian on Saturday.
Defending French champions PSG were the beneficiaries of some good fortune as Nice defender Timothee Kolodziejczak turned the ball into his own net seven minutes into the second half.
The left-back looked to have been pushed in the back by Edinson Cavani in the lead up to the goal, which was allowed to stand as PSG claimed their 23rd league win of the campaign.
Blanc's focus will now switch to Wednesday's game against Chelsea as PSG look to reach the Champions League semi-finals for the first time since 1995.
PSG were the first to threaten the goal as midfielder Yohan Cabaye shot narrowly wide from long range, but it was Nice who looked to have taken the lead in the 10th minute when Dario Cvitanich nodded home from a free kick, only for the goal to be correctly disallowed for offside.
The visitors responded excellently to that scare and could have gone ahead, only for Ezequiel Lavezzi to miss the target with a glorious opportunity after being played through by Zlatan Ibrahimovic.
Nice did cause the PSG defence the occasional difficulty but it was Blanc's men who continued to create the better chances, Cavani drawing a fine save from David Ospina before Marquinhos headed wide from the resulting corner.
Ospina quickly became the star of the first half, producing further heroics to keep out a fierce effort from Ibrahimovic and a header from Thiago Silva - sporting a facial mask to protect his cheekbone - shortly before the interval.
But the Colombia international was finally beaten seven minutes into the second half as Ibrahimovic headed Javier Pastore's cross into the path of the unfortunate Kolodziejczak to bundle home.
Eric Bautheac did come close to equalising for Nice from a free kick, but Claude Puel's hosts were grateful to former PSG midfielder Mathieu Bodmer for keeping the deficit at one.
Bodmer showed great determination to prevent a goal-bound effort from Lucas Digne from finding the net, as Ospina lay stricken on the edge of the area after thwarting Ibrahimovic.
But those efforts proved to be in vain as Nice wasted a last-gasp free kick and PSG held on to take another step towards a second successive title.