It depends. If you intend to move, then you must make sure that Dad knows exactly where his son is living. Whether or not you will have to move back depends on whether Dad files a timely petition and ex parte action to have you return.
Counsel offers you excellent advice. If you decide to move, make sure Father knows where son is. Best of luck to you.
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Accord with Ms. Farley's excellent response. If you can, seek written permission from your husband to move to Nevada with your son. If he gives you his written permission, that could help to avoid custodial problems.
Please note that this answer does not constitute legal advice, and should not be relied on, as each situation is fact specific, and it is not possible to evaluate a legal problem without a comprehensive consultation and review of all the facts and court pleadings filed in the case. This answer does not create an attorney-client relationship.