I want to set a field on a work order based on another field. I generally use userevent scripts but this work order is generated from a parent work order. Will a userevent script work?

UE should trigger on create. You can run a quick test to verify, though. They won’t run if the WO was created through a User Event itself, which doesn’t seem to be the case, here.

Isn't behind the scenes netsuite using a user event script?