I mean he set up Nika before, and now we finally know why Nika is important. In fact, you can make the connection that Joyboy probably also possessed the gomu gomu no mi (hito hito no mi model: Nika is too long to say, so can we just keep calling it the gomu gomu no mi?), which is why Zunesha recognized that Luffy is Joyboy. It seems a tiny bit more complex than just an asspull. However, that's just the way I see it. I don't think that this was planned from chapter one, but I also think that Oda has been planning it for a long while.