I think a lot depends on which curse word was used, and the context in which it was used. If the nurse was responding in kind to something like "Eff you", that is entirely inappropriate and she should at least receive a written warning. However, if the resident was teasing and she parroted back the curse word, that's another kettle of fish entirely and a verbal reminder about language should suffice.
Of course, I wasn't there and thus don't know
the context, so I echo the other posters in saying that we really can't advise you or make an intelligent guess as to what the management will do in this case. It does seem a bit over-the-top to suspend someone for single curse word, but again, it all depends on context.
Personally, I've cussed in front of a resident before, but only when I knew the resident didn't mind it. Even so, I've never used foul language, only the occasional "damn" or "oh crap" if I do something irritating, like drop an armload of clean linens on the floor.