If the mod can't be acquired through Nexus, look elsewhere. I found it on the first page of a Google search for "Naruto Ultimate Overhaul". You lucked out, normally this method is bunk and you just have to hope the mod author re-uploads somewhere other than Nexus. For future reference, if a mod seems like it's gonna have a copyright issue on Nexus, download it and back it up immediately because Nexus does not tolerate copyright infringement and will nuke a mod in a heartbeat over it whereas Steam is a lot more tolerable. In your case however, I would try and figure out why the mod CTDs when it is loaded into your game since the author seems to deliberately want to support only the Steam version.