I think that Nid is a meh champ. I mean, I play to have fun, but if you're playing ranked or trying to win, I wouldn't choose her.
Yeah, she has the heal and traps n' stuff to make her never get out of lane. But, imo, she scales shitty into later game. And from my experience, top lane usually is someone who scales pretty well into later game (or seems like a top laner should for my preferences).
But if you're good with her and outright win your lane, by all means, don't stop playing her. You have fun playing what you play.