How would Putin even deploy nukes on the battlefield? Are their any targets large enough to warrant a tactical nuke strike? I don’t see it increasing his chance

How would Putin even deploy nukes on the battlefield? Are their any targets large enough to warrant a tactical nuke strike? I don’t see it increasing his chances of winning. He could hit Kiev with strategic nukes I guess but he dooms all of Russia no matter what. Really, his nukes are useless here. He gains nothing by using them and risks everything.