the counterfactual is 'is there an equally qualified nurse who didn't get the position?' There is a lot of under-employment for highly qualified US citizens.
Long term shortages are evidence of supply controls or price controls. If nurse compensation was allowed to rise to its natural level the shortages would solve themselves. High compensation pulls people into a profession. Suppressing compensation with imported labor cures a short term problem but creates a bigger long term problem.
Hmmm, so a nurse can come from any country with any level of English and work in a US hospital without re-certification? There is a smell to this claim…