How to make gods not a Deus Ex Machina

Well a Deus Ex Machina is when someone at the very end comes in and saves the day, resolves the story, and it completely comes out of nowhere. If you have a character die and then come back, that isn't really a Deus Ex Machina. It's more like Gandalf. So long as the resolution of the plot, the climax, doesn't revolve around this god then just saving the day, so that all our investment in the peril of your MC and the MC's struggles, become pointless through the actions of the god (ie: a quest for a cookie, evil cookie gangs chase the MC, the MC finally gets into the store and is surrounded by cookie ninjas and then suddenly everything goes black and when the MC wakes up she finds the god smiling and handing her the cookie. Well I say that isn't fair, at this point as a reader I want to see the MC get the cookie for herself!), I'd say your good.

Deus Ex Machina is when the author can't think of any way to get his characters out of the deep mess he's written them into. So, at the climax, he writes a never-before-mentioned god to come swooping in and fix everything for them.

That's not even close to what you're describing.

I don't know where you heard any rule about one resurrection per story. Establish very early that resurrections are possible and show how they work. You don't want them to be a get-out-of-jail-free card, but as long as they have some kind of cost or negative consequence (even if it's minor), go for it. Write as many resurrections as your story needs.

I agree with everything Toothpaste said.

Personally I hate the deux ex machina ending because it is just so so cheap. It ruins books for me and is one of those things that will make me stop reading that particular writer. I also hate when an author makes something impossible for the main character ie they can't have children because of a war injury but at the end of the novel they magically can because the gods are rewarding them! (Gods who are not involved in the story directly at all before this point). Now that isn't deux ex machina either because the actual plot was resolved by the main character, just a little pet peeve of mine. (Though I really loved the rest of the book up to that happy happy end but maybe I'm just cynical.)

Okay sorry for the rant.

As for your original question, no, I don't think bringing back the god character is cheap or deux ex machina in any way. In can actually work out brilliantly. Also I don't know about anyone else, but I would assume that gods would be immortal even if they aren't omnipotent. As for doing it more than once, I say it would still work because you have already set the rule that the gods can not die this way and so if it happens again the reader will expect the god character to come back. Now if you tried to do a twist and the god character was really dead, then I think there would be a problem because it would contradict a rule you already created.

So long post short, it is your world, make whatever rules you want as long as you establish them. I personally don't see anything wrong with the idea that you posted so I say go for it!