What's the difference? SpotPass TV is original content produced by Fuji TV and Nippon TV, all in 3D, and delivered daily; Nintendo Video, according to Andriasang, offers periodic releases of 2D and 3D content "recommended" by Nintendo.
It's quite likely that two teams were working on two services, and Nintendo just released them both. Still, with the eShop finally merging the "shopping" and "ranking" functions for downloadable games, it's odd to see another offering split into two apps along arbitrary lines.
As is the trend for Nintendo now, this service is coming to Japan and Europe well before any news of an American release. It could show up here with the eShop update this Thursday, with content specific to the North American region ... or never.
Update: Nintendo of America told us that its own "short-form video service" will be available "later this summer," and took the opportunity to remind us that Netflix is still on the way to 3DS. The statement is after the break.