I don't live in Nevada, but have carried there and have looked up the rules. If a casino has a "No Guns" sign, it's my understanding that it is unenforceable. If someone spots your gun, they can ask you to leave, at which point you must, or you can be arrested for misdemeanor trespassing. The only exception is carrying in buildings that are specifically prohibited by law.
That should have the info you need...and of course, since I don't live in Nevada, it's entirely possible that I missed something and I could be wrong.