I've deduced this to be qoqoa's video based on that Niconico channel's two videos being uploaded very close to when they were uploaded on qoqoa's now-deleted YouTube channel. There doesn't seem to be public archives to demonstrate this (consult my metadata archive for that), but I can confirm that this was originally uploaded on YouTube in this address: https://www.youtube.com/watch?v=nkfJn8UXf8Q