Leo,
The same question could be asked about Microsoft and Sony. However, I will answer your question. Nintendo has developed a number of games based on Disney Characters for their portable consoles.
Also, Disney is using modified DS units for the Disney Magic Connection, which is a Wi-Fi-enabled interactive guide, map and informational tool for guests attending the park. The software offers an interactive map of the Magic Kingdom, with guides to various "park offerings" including rides and dining locations, meet-and-greet locations for characters, and a wishlist checklist that allows you to mark off attractions after they've been visited. It also appears that the map will give "you are here" information, presumably by figuring out the Wi-Fi access point to which your DS is connected.
Supposedly, while in line waiting for an attraction, themed games will be unlocked. This feature may or may not be present yet.
More importantly though, The Mario Universe and the Magic Kingdom fit together perfectly.
If Nintendo is successful at the moment, it’s because they are good, and I cannot blame them for that. What we should do is try to be just as good.----Laurent Benadiba