Is it legal for me to move out of state with our son if my ex and I have no custody agreements?

Is it legal? Yes, in that it is not kidnapping. Could it have serious consequences, including your ex obtaining custody? YES. This is a hotly litigated issue, and somewhat in dispute under current Nevada law. Your best course of action is to either have your ex's permission in writing, or to get permission from the court by filing the proper paperwork.

No. The Nevada Supreme Court just addressed that question, and the same rules apply as to everyone else - presuming paternity has been established, you need consent of the other parent, or a court order, to relocate without concern of a change-of-custody motion being filed against you.