Back in 2015, Nintendo announced that going forward it would only allow monetization of videos featuring Nintendo content by channels approved through a special Nintendo Creators program. The program included numerous restrictions, an often lengthy video approval process, and a revenue share that gave Nintendo up to 40% of the profits. It was not a well-received program, to say the least. Now, three years later, Nintendo has just announced that they're putting an end to it.
In a short statement on the Nintendo Creators Program website, Nintendo announced that the program will be shut down by the end of the year, and the website itself will cease to exist after March 20, 2019. Nintendo says they are taking this step in order to "make it easier for content creators to make and monetize videos that contain Nintendo game content."
It's unclear if new protocols will replace the old ones in time, but for now, Nintendo will no longer be requiring videos to be submitted for a review process, which previously could take as long as three days at times. As long as you follow Nintendo's official guidelines for uploading video content, you should be free to monetize without a special license from Nintendo.
Source: Nintendo Creators Program