Im pretty sure theres no amount of Kyuubi chakra that can heal him from Amaterasu unfortunately....its the flames of hell after all lol.

I like the idea though, its pretty cool sounding but I wonder if he is inside this giant rasengan with wildly spinning chakra will he not get hurt? Maybe if he learned a good wind chakra defensive technique that would help, he could just blow away the flames and whatever comes his way I think.