Read your lease and get yourself familiar with what your rights are.
Your landlord is violating the provisions of your lease.
More importantly, your landlord is violating NEVADA law.
Please see the underlined portion of the law, below.
You are entitled by law to injunctive relief, and damages.
You can also break the lease and move, LEGALLY.
I'd recommend you do the latter.
You should immediately speak with a lawyer in your city!
Proving what this creep is doing will require some help.
You might need to purchase a small surveillance camera to catch this bum.
Your landlord might very well be a perverted creep, or potential sexual assailant.
Here is the law in NV, regarding tenant privacy.
NRS 118A.500 Tenant's refusal to allow lawful access to dwelling unit; landlord's abuse of access.
1. If the tenant refuses to allow lawful access as required by the rental agreement or this chapter, the landlord may obtain injunctive relief to compel access or terminate the rental agreement. In either case the landlord may recover actual damages.
2. If the landlord makes an unlawful entry or a lawful entry in an unreasonable manner or makes repeated demands for entry otherwise lawful but which have the effect of unreasonably harassing the tenant, the tenant may obtain injunctive relief to prevent the recurrence of the conduct or terminate the rental agreement. In either case the tenant may recover actual damages.
(Added to NRS by 1977, 1343)
http://www.leg.state.nv.us/NRS/NRS-118A.html