You'd probably have to wait for Nikasaur herself to respond to be sure, but from what I know about Youtube, Copyright, and the art they accept, I think it would be fine.
Notch, the creator of Minecraft, actively encourages people to put things up on Youtube and do creative stuff with it, etc. so I don't think there's much chance of the showcase running into legal trouble for putting up footage from this specific game. In my own Youtube career, I have yet to run into any problems uploading or even monetizing Minecraft gameplays.
Hope it helps! Best of luck with the art.