Not originated by the Animaniacs, this was a running gag in vaudeville... a catcall to call attention to a fine looking individual passing by.
*scantily clad curvaceous person sashays into line of sight*

"Hello Nurse!"

or more appropriately

"Helllloooooo, Nurse!"
by djtonyb August 7, 2009
Derived from Animaniacs, a person who is so visually appealing to all that you must draw attention to them by saying "hellloooo nurse".
**walking down the street when the hottest looking guy ever walks past you, you whistle appreciatively, turn to your friend and say "hello nurse".
by Animaniac January 31, 2004
A New York City based pop-punk band with a unique sound.
Hello Nurse the band.
by SZenn September 9, 2006