Per NRS 484A.600, speed and red light cameras are illegal in Nevada, except under special conditions. They can be hand-held by an officer or mounted to a patrol car or police building, but they cannot be placed as fixed installations on the road or at signal lights.
There is a loophole in the law which allows private entities such as Home Owners' Associations (HOAs) to place speed cameras on private property. However, as those do not have an impact on the public as a whole, they are not added to the Waze map at this time.
A number of drivers are unaware of this, and often mistake traffic control cameras for red light or speed cameras, and will add them via the app. Just delete those cameras. If the person who reported the camera has taken the time to set up a forum account, you can contact them via PM to inform them of the deletion and to point them to this page.