Is it possible to disable the Files tab from the Chat Window in Teams

kensleylewis I don't think this is a good idea, people will just email files to each other and you'll lose the benefit. You are unlikely to have a team or channel for every interaction that happens in your business, there's always adhoc things that sit outside this structure.

Chats, even group chats are clearly perceived by users as fairly temporary structures, teams are longer lived, I've never seen it come up that information is lost in group chats. To be honest I don't really see very many real group chats at all, that happens in the teams.

In simple terms I think the answer would be to prevent them sharing files in OneDrive, then the feature in Teams will not work. There is no specific control to disable sharing in chat, you can turn it off entirely in a Messaging Policy.