Well, actually many chicken love to sleep in the nests...About the coop...chickens prefer to roost in a different location other than nest box. Most chickens use the nest box for laying eggs only. They should have a roosting bar ( or a couple) as well. If you don't have roosting bars..your chickens will be eternally grateful if you would accommodate them. I got the impression from your post that perhaps there are only nesting boxes in the coop?
...it's us keepers that are not fond of that.
Those tiny coops often are not set up well for roosts to be higher than nests,
so you end up with poopy eggs unless you do some modifications...or daily cleaning.
This is one of the best mods I've seen:
http://www.backyardchickens.com/t/1134399/help-hens-roosting-in-nest-boxes/10#post_17749535