Depending on the country where the medical training was obtained, and what certifications are available documenting the training and later experience, some training in the US way of doing things is likely necessary to obtain a license. An acquaintance, a pediatric critical care specialist from Bolivia found he would have to repeat a residency to obtain a Virginia license. He decided to work in IT in a hospital working on AI implementation into the hospital systems. An inquiry with the NJ State Board of Medical Licensure is the place to start. Finding a residency in the specialty of interest and talking with the director of it may be worth the time and effort.