Want to know more about Nardole and Matt Lucas? This video has Nardole answering questions for a Youtuber named Crispy Pro.
Earlier we asked "Why is Nardole still around?" Because, well, it's kinda strange that a person presented as River Song's side-kick, and then disassembled and inserted into King Hydraflax's body, would be able to reappear as a functioning person helping the Doctor. But then this is Doctor Who.
Unfortunately our curiosity isn't answered by Matt's answers. He's very good at saying things and being funny without really answering questions or saying anything of substance.