The Spanish second seed, also looking to equal Roger Federer's men's record of 20 singles Grand Slam titles, was never bothered on court Philippe Chatrier.
World number three and US Open champion Dominic Thiem survived a third-set wobble to beat American qualifier Jack Sock 6-1 6-3 7-6.
The Austrian third seed has been beaten by Nadal in the last two Roland Garros finals.
And three-time Grand Slam champion Stan Wawrinka said he was ready to challenge for his second French Open title after a comfortable 6-3 6-2 3-6 6-1 win over German Dominik Koepfer.
The 2015 Roland Garros champion put his muscular build to good effect to hit 51 crunching winners despite the slow conditions on Court Suzanne Lenglen in his first career meeting against the 61st-ranked German.
"I'm ready for it. I've been practising right. I'm feeling good. I like the condition here. I enjoy being back playing Grand Slam. It's great to be able and have the chance to play this year French Open," said Wawrinka.