The defending champion, chasing a record-extending 12th title at Roland Garros, powered through the first two sets before being slightly bothered in the third.
But the second seed from Spain, who looks to become the first player to win a Grand Slam title 12 times, stayed business like when Maden broke back for 4-4 and the contest ended when the world number 114 returned wide.
"He's a good player, he had won four matches -- three in qualifications -- going into this match, he had gained confidence," an always gracious Nadal told a courtside interviewer on Court Suzanne Lenglen, where he has never lost.
His only two defeats in 90 matches here happened on the main Court Philippe Chatrier.
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"For me it is an important victory, playing here in Paris, at Roland Garros, is always incredible," the 32-year-old added.
Nadal will take on David Goffin, the 27th seed, for a place in the fourth round.
Goffin has never snatched a set from Nadal in three encounters on clay, but the reigning champion is wary of the Belgian's threat.
"He's a very complex player. He has all the shots. He's a player who has an amazing career, and we practiced a lot of times," Nadal told reporters.
"We know each other well. He's an opponent that you need to play very well against. He is quick. He has very good angles.
"It's going to be, being honest, a big challenge to be in the third round. Here we are. I'm going to try my best to be ready for it."
(Reporting by Julien Pretot; Editing by Emelia Sithole-Matarise and Christian Radnedge)
