Neither a nondisclosure agreement (NDA) or a noncompete will keep anyone from stealing your idea whether in the U.S. or abroad. Agreements don't prevent wrongdoing, they merely establish the rules in the event wrongdoing occurs. An NDA is no different. For example, your NDA may establish the location of the lawsuit, whether the winner gets attorney fees, whether arbitration is mandatory, or the ease with which you can get an injunction.
Back in the U.S.A. NDAs enforced in the U.S. usually have a predictable outcome. But once you leave American jurisdiction, the results of enforcement are not as predictable and the costs of enforcement are far more expensive. That increases the odds that your NDA will be breached and that a foreign manufacturer will duplicate molds, copy packaging and send knockoffs out the backdoor and into countries in which you have no intellectual property rights.
Separating the good from the bad. Most foreign manufacturers rely on their credibility and trustworthiness to keep getting new business. So your first goal is to do your homework and try to figure out which ones are reliable and which ones are opportunists. The resources, below, may help you.
Protecting secret stuff only. Keep in mind that a nondisclosure will only protect against the disclosure of confidential information. Once your patent is published, it is no longer confidential. So the only thing your NDA can actually protect is confidential information regarding manufacture, sales and distribution, and know-how needed to produce and distribute the patented item. A noncompete is typically aimed at preventing ex-workers from competing against you and that's not likely to provide much benefit. However, some provisions, in conjunction with your NDA -- for example, an agreement that the manufacturer will not manufacture or distribute your product without your authorization -- can be crafted to deal with your specific situation. A lawyer's assistance may be required. In summary, get an attorney to make sure the agreement provides the best dispute-resolution procedures.
Your lawyer may include provisions that will help you in a foreign deal. Here are some things to consider.
These resources may help you sort out manufacturers in foreign countries: