"So Mr Zim, you're accusing X of using your copyrighted code. But you've admitted you used AI to generate that codebase, so you don't own the copyright. Please prove exactly which lines of code you do own the copyright to?"
Depending on what logs exist I could probably find lines of code which definitely aren't AI generated. Of course, in practice I wouldn't bother and would sue using trade secret laws instead where no such issue exists.