Iwata believes that the Ubisoft dance title was one of the most important titles of 2010.
http://www.nintendoworldreport.com/news/24979
Nintendo has announced via their quarterly financial statement that they will be publishing two third party Wii titles in Japan: Activision's GoldenEye and Ubisoft's Just Dance 2. The success of Just Dance 2 prompted Nintendo to publish the title overseas. Nintendo Co. Ltd. President Satoru Iwata believes that Just Dance 2 was one of the more important Wii titles in 2010, outperforming Donkey Kong Country Returns in November and December in North America.
This wouldn't be the first time Nintendo has published third party titles in Japan. Sega's two Mario and Sonic at the Olympic Games titles were published in Japan by Nintendo. In addition, Nintendo published Harvest Moon: Tree of Tranquility in Australia.
As far as I can gather, Goldeneye on the Nintendo 64 sold decently in Japan, so perhaps that has something to do with Nintendo publishing Activision's version of the game in Japan?
I don't think they publish their own games in Japan (at least they didn't have any games in the top 100 of 2010, and I don't recall seeing them in the weekly charts).