I started out by immediately defending the nurse, but also will defend the 911 operator. Because of reality. There is no qualified medical professional in the room where 911 operators answer. IF it is a no-breathing and no-heartbeat situation, the person is DEAD before the 911 operator could get and convey competent medical advice.
911 operators get ever imaginable situation of every possible kind. IF it APPEARS immediate life-death, the 911 operator - whether as an employee or as a fellow human - has to do the best she/he can. Sometimes they get it wrong. But at least someone is trying to be level headed with some rudimentary knowledge that is a little bit about almost everything and expertise at nothing.
Finally, a person is generally NOT liable for advice they give to someone else. If you told me some situation and I replied, "hell, you ought to go punch that SOB in the nose!" and you do, I am not a co-conspirator in you being guilty of assault.
There is a misconception of what 911 is. They are message takers and info conveyors - and nothing else legally. What they say has no legal weight either way whatsoever - other than MAYBE to show good intentions of the person if following 911 advice. BUT, ultimately, the decision to follow that advice or not always comes down to the individual.
If 911 operators were liable for advice, then all a 911 operator could say is "let me get your number and I'll get a message to everyone so everyone can decide who should do something - if anything - and maybe someone will come or call you back - or maybe not" - and hang up. If the person asked "what should I do?" all the 911 operator could say is "sorry, I can't give advice to anyone."