Actually, yes. You have to have at least one DLC pack bought. Then you need to delete that pack (or just rename it if you want to keep it), and then use DLC Tool and create a DLC file with the same name as the pack you renamed, and put all your nude costumes in there. You won't be able to use the costumes that came in that pack, though, unless you first extract them and manually add them back in to your new pack.