Yes. Squatting in Nevada subjects the alleged squatter to not only civil lawsuits but also criminal charges. Squatting prosecutions have been on the rise due to the increasing number of unoccupied homes in Nevada as a result of the 2008 housing crash. With so many empty houses in the valley, it may be easy for people to move in without anyone noticing.
Unlawful occupancy (a.k.a. "squatting") is defined in Nevada under NRS 205.0817 as taking up residence in a vacant dwelling without the owner's permission. The main element of squatting is the knowledge that you have no permission to live there. It does not matter whether you have permission to enter for a temporary time (such as to clean the dwelling).
Squatting in Nevada is a gross misdemeanor carrying up to 364 days in jail and/or up to $2,000 in fines. But a fourth or subsequent squatting conviction is a category D felony carrying one to four years in Nevada State Prison and maybe up to $5,000 in fines.
Common defenses to squatting charges in Nevada are that the building does not qualify as a dwelling, that the defendant never took up residence, or that the defendant reasonably believed he/she had permission to live there. (For more information, see our articles about the difference between home invasion and burglary in Nevada and how housebreaking is different from squatting in Nevada.)