She will need to sit on all stages of the United States Medical Licensing Exams and will need to be sponsored by the Educational Commission for Foreign Medical Graduates.
If she already has been tentatively hired by a hospital as a resident, it should be no trouble for her to be granted permission to sit on the USMLEs.
Any specialty training she has done will have to be re-done, as will internship and residency. In some cases, internship is not necessary to repeat, but often it is done as a probationary period before the actual, contracted residency begins.
Assuming she already has a spot in a hospital's residency, and has no trouble with the USMLE, then I'd say her prospects are pretty good ... at least as good as any other young doctor in the U.S.
If this post is wondering about average pay ... Last I knew, residents make somewhere around 35,000-45,000 USD per year depending on where you are. Keep in mind that is what you are salaried for working approximately 80 hour work weeks. That basically translates to about the same (per hour) as what an average secretary or janitor makes in the U.S.
Salary and hours worked both drastically improve as you get into specialty and after you have finished all your training ... which, depending on area, can take 5-10+ years.