The phrase "nice nap" means to sleep for a short time, usually in a comfortable and peaceful manner.
Sentences with «nice nap»
Well, I can't say I've slept on it overnight, but I have had a few nice naps on it! (hookedonhouses.net)
I must also say the extra hours saved on Sunday is sooooo nice; it might not seem like much but I've gotten a lot done in those 2 1/2 hours, or had myself a really nice nap. (redeeminggod.com)