You'd be surprised. Games like this get shutdown all the time, ESPECIALLY when they're about to come to fruition. Namely every single Chrono Trigger remake game I've looked out for (despite the fact that Square-Enix isn't even doing anything with the IP).
Despite the fact that this won't make money (most fan projects claim not to, and don't), it's still a violation of IP laws. I sympathize. I'd love to see more fan projects out there make it, but companies DO send cease and desist letters. Example:
http://www.chrono-trigger.com/
However, I can't find any sort of example of Nickelodeon stopping a fan game, but maybe I'm just not digging deep enough, so you just might be good. But don't count on it. But the upside is, if they do catch you, they won't sue you. Unless you continue after they tell you to stop. So you won't lose anything from your own pocket, just your time, on the off-chance they catch you.
As for the actual game itself, it looks like you've got a nice community (I only took a cursory glance, sorry), and I can't see that small movie posted on your forums (someone changed the URL?), but it looks good! Good luck!
