Still, it does show that its not OOC for Chat Noir to use Cataclysm on a person, and additionally the comment by Gilded Star regarding Sole Crusher shows that if the push comes to shove Chat would most likely use Cataclysm on living people in a desperate situation if necessary, and not necessarily while blood lusted (even though his comment was meant to suggest that Chat would only use it akumas).
I think that Thor stomping him would count as one of those desperate situations, and a situation in which Chat would likely use his power on Thor. Plus with speed equalized its not like Chat Noir would not be able realize that Thor is stronger than him since there is no way for a speed blitz to occur in either characters favour.
Also completely unrelated topic, but I made a post arguing for
Chat's upgrade to 7A in his base, and I think people should check it out.