No, no, no, no.
Just get WORDS ON THE PAGE. Then put them right when you edit AFTER nano.
The point of nano is to have fun, not to write a masterpiece. Sometimes a masterpiece happens, sometimes it's disposable; but there's lots to learn about yourself as a writer by writing so much in so little time.
Me, I'm still a bit behind, but trying to catch up slowly. Determined not to be a perfectionist this month, otherwise it'll slow me down. I'll let my "Inner Critic" loose later, when I do the edit.