I'm fairly new to Invasion, so forgive me for this relatively noobish question.

Say I'm Chaos and I have the Warpstone Meteor in my Kingdom. It has 2 Power on it, which basically gives me 5 Resources per turn. But then the opponent decides to attack me and goes after my Kingdom. I have no units there, only the Warpstone Meteor. Does the 2 Power on it allow me to assign two damage to the attacker as if it was a defending unit even though it's a support card, or can only units do damage? I'm assuming the latter, but I want to make sure. Thanks in advance to those who answer.

nope

the power on SUPPORT cards, unless specifically stated by the cards, DOES NOT does not count as damage in regards to attacking or defending.

So, typically, there is no good reason to put a support card with power in the battlefield, unless there is some text on the card that gives you another reason to do so.

That's what I thought. I figured the power only counted to how many resources you got or how many cards you drew. Thanks.

This is covered in the rulebook if anyone tries to argue this with you.