question

Nately's whore tries to kill Yossarian a) because she has no one/nothing else to vent her overwhelming anger for the shock of bringing the news, b) because she still thinks (or doesn't, but just hates him because he brought the news) Yo-Yo killed him indirectly or directly, and c), from the take at the end of the book, she just wants to kill somebody.

I would like to give you a brief history of the inside of my pants.
-Stephen Hawking

As badarsemotherk stated, Nately's whore wanted to kill Yossarian because she (irrationally) blamed Yossarian for Nately's death.

The madness and irrationality of Nately's whore blaming Yossarian for his friend's death just because he was the one who brought her the news was part of the point of "Catch-22."

The entire book was supposed to be irrational and so was Nately's whore's hate for Yossarian.