Battle takes place on Mars. Thanos has prep
We did see Ex Nihilo put on his ass by Hyperions heat vision which is not a good sign. I think Thanos could withstand that. Then again he didn't see the attack coming.
He was also extremely hurt by Thor's lightning...
Ex Nihilo needs more showings. He's supposedly omnipotent for his ability to create life but I need to see more. The fact that he was hurt by Thor and Hyperion and Thanos merely flinched from two of Thors powerful lightning blasts & a hammer shot from outer space kinda states that Thanos is superior in the durability department.