That was acidic chakra that flakes the skin off. This isn't purified KCM Chakra. So, in reality, she not only withstood the effects of Gravity, but Naruto's chakra as well.
Kyūbi cloak shielded Naruto's clothing (i.e. why he was able to reform from his enrage, in an unscathed outfit). Katsuyu was present in Naruto's clothing, protected by the Kyūbi's shroud. Chibaku Tensei would work.