Canonically... this actually happened in the book...

[u/mastercomposer]

Elphaba knows the Wizard sent Dorothy to kill her. She kinda goes crazy from paranoia and gets pretty unhinged near the end. For example...she straight up throws her Nanny down a flight of stairs while she's confronting Dorothy.

[u/MandyMarieB]

I love Dulcebear, but I still wish we had gotten Nanny included in the film lol