I have no idea what Nintendo is thinking. It seems that they are trying to dig the biggest grave they possibly can.
Lets Play videos give games publicity, when popular youtubers play it and give good feedback, it inspires others to buy the game for themselves. I think it's incredibly selfish and stupid that they are trying to make money off of Let's Plays. It just makes Lets Players not want to play their games at all, unless they are completely devoted to Nintendo Games and nothing else.