First of all, like everybody says DON'T FEEL BAD PLEASE !!
Don't let this incident eat you up inside or let that nurse make you feel that you are not a competent nurse. I can see how insulting it would be if another nurse was questioning my " nursing judgment ". I know how you feel cuz I have to deal with somebody like that almost everyday. Totally unreasonable nit picking.
These are the things that i do for the sake of my sanity..
1, Usually i will pretend that i'm having difficulty hearing things when she is about to start to say something unreasonable again. simply no verbal response. Hmm.. i think i hear dog barking somewhere.. do you hear that too? kind of attitude.
2, Sarcastic attitude , for example, " OMG!!!!HOW ON EARTH DID I FORGET TO GIVE O2 WHEN O2 SAT WAS 98% RA OMG!!! IS SHE STILL ALIVE??!? " - requires some level of acting skill but practice makes it perfect right?
Remember do not allow her to take your self-confidence away from you and stick with what you believe is right and do your best.