I have a roommate, he move in 2moths ago, he disturb peace in the house w all the fight and drama between him and my brother, he is always causing problems at the house, he just told me he is leaving! BUT! 30MINS LATER he said according to the law of Nevada I can't evict him! So I don't know what to do, because I'm just tired of this, I want him to leave but now he don't want to. What can I do?

What law does he think doesn't allow you to evict him? As long as you follow the legal process you certainly can evict him. This site outlines the process: Nevada Evictions (http://www.rentlaw.com/eviction/nevadaeviction.htm)

You should be able to serve him a 3 day nuisance notice. Then follow it up with going to court for an eviction order.