It depends on where the other parent is located. If the other parent is in Nevada, then you do not need permission to return to Nevada. Otherwise, the permission you got to move to Texas does NOT apply for you to move to any other state. Keep in mind that any significant change in location will require a change in the visitation schedule.
Responses are for general information purposes only, and are based on the extremely limited facts given. A consultation with an attorney experienced in the area of law(s) indicated in the question is highly recommended. Information and advice given here should not be relied upon for any final action or decision, as the information is limited by its nature to the question asked and the fact(s) presented in that question. THIS RESPONSE DOES NOT CREATE AN ATTORNEY/CLIENT RELATIONSHIP, particularly considering that the names of the parties are unknown.
It may also be affected by any orders from Texas, if the prior order was domesticated and the Texas court took home-state jurisdiction. If the relocating parent did not get permission from the Texas court, then they would be expected to return to the Nevada courts to obtain permission and to assure that the visitation schedule was modified accordingly. Of course, you can alway consent to the move yourself, which would put home-state jurisdiction back in Nevada (assuming a 6 month residency requirement were met), making enforcement of a Nevada order just that much easier.
The order allowing the parent to relocate to Texas does not extend to any future relocation. If both parents agree to the relocation, then get it writing. If the non-moving parent disagrees, then the moving parent will need a court's permission to relocate.