Mbappe on target as PSG beat Nice to reach French Cup semi-finals
Having only been used as a substitute in last weekend's 2-2 draw with Reims in Ligue 1, Mbappe was recalled in one of six changes made by coach Luis Enrique.
He responded by opening the scoring in the 14th minute at the Parc des Princes, and Fabian Ruiz soon doubled the home side's lead.
Gaetan Laborde pulled one back before the break for Nice, but Brazilian defender Lucas Beraldo's first PSG goal sealed the win on the hour mark.
Ten points clear at the top of Ligue 1 and through to the Champions League quarter-finals, the result means PSG remain in with a chance of winning a clean sweep of honours this season.
"The team has clearly improved and I think we will keep improving," said Luis Enrique.
"We are in a key moment of the season, into the final third, and we are still alive in every competition. We need to remain humble and try to be even more competitive, but we are in great form."
The capital side, record 14-time winners of the French Cup, will now play Rennes at home in the semi-finals on April 3, with Lyon hosting second-tier Valenciennes in the other tie a day earlier.
PSG have won the competition six times in the last decade but failed to do so in either of the last two years. This year's final will be played in Lille on May 25.
Mbappe has either started on the bench or been substituted in each of PSG's four Ligue 1 games since he informed the club of his intention to leave when his contract expires at the end of the season.
However, he played a starring role as the Qatar-owned outfit beat Real Sociedad in the last 16 of the Champions League, and Luis Enrique has indicated he will also continue to field the France captain from the start in the domestic knockout competition.
'This is not an NGO'
The coach's squad rotation has created headlines in recent weeks beyond his use of Mbappe, but the Spaniard made clear he does not mind leaving key players out.
"I don't care. It's normal that the players are not happy when they don't play," he said.
"They need to be prepared to give 100 percent when they train and when they play.
"This is not an NGO, it is a top-level football team. The players need to be ready to perform at their best. Whether it is fair or unfair is not my concern."
Mbappe, wearing the captain's armband, got the breakthrough when he played a quick one-two with Ruiz in the box and poked the ball over the line for his 35th club goal of the season.
Goncalo Ramos blazed a great chance over and Mbappe saw a deflected effort hit the post, before a goalkeeping error allowed the hosts to increase their advantage just after the half-hour mark.
Marcin Bulka, Nice's giant Polish shot-stopper, made a mess of dealing with a back-pass under pressure from Ousmane Dembele, who seized the ball and laid it back for Ruiz to score.
Ineos-owned Nice are the only side to have beaten PSG domestically this season, having won 3-2 at the Parc des Princes in September.
Second in Ligue 1 at the season's halfway stage, their challenge at the top of the table has faded on a six-game winless run.
They pulled a goal back on 37 minutes when Gaetan Laborde controlled and lashed in a rocket of a shot after a good run by Jeremie Boga.
Nevertheless, PSG effectively ended any prospect of a Nice comeback on the 60-minute mark when a Vitinha cross was headed in at the back post by Beraldo.
The 20-year-old defender has quickly become a regular in the Paris side since arriving from Sao Paulo in January.
Shortly after that, a Lee Kang-in free-kick was tipped onto the bar by Bulka, who needed lengthy treatment after taking a knee in the face from Ramos and being left with a bloodied nose.