Thiev'n Varmints (Red)

Thiev’n Varmints triggers when it resolves and becomes an attacking card This is an optional effect: You choose whether or not to remove a gold counter from Treasure Island at the time the triggered effect resolves. If you do and your hero is a Thief, you will create a Gold token.

Unless a rule or effect allows you to do so, you cannot declare defending cards against attacks where the attack-target is an ally you control.

There is no priority between removing a gold counter and creating a Gold token