It shall be an unlawful employment practice for an employer to fail or refuse to hire or to discharge any individual, or otherwise to discriminate against any individual with respect to his compensation, terms, conditions, or privileges of employment, because of such individual's race, color, religion, sex, or national origin
Well, if you want to get very technical, you could say the "conditions" of employment were somewhat altered in one single situation. In every other respect, nothing about the terms of employment changed. The problem is that the complaint has to navigate a very narrow window for "damages."
The nurse would essentially have to make the argument that she was harmed by not being exposed to a racist client, or suffered serious psychological harm from having a supervisor dare consider not wanting to expose certain staff to one.
Thin at best. There's a case there, but it's not much. It will settle, but I'm sure the terms won't be disclosed when it is.