At least for Nix itself, that's pretty much it except via Dutch.
> The name Nix is derived from the Dutch word niks, meaning nothing; build actions do not see anything that has not been explicitly declared as an input
From page 81 of the original paper: https://edolstra.github.io/pubs/nspfssd-lisa2004-final.pdf
That's surprising; nix is Latin for snow, and its logo is a snow flake, so I just assumed it was that.
Also, I think the founder's username in various places is nixnut. Which to an English-only speaker means someone crazy about Nix (Nix fan). However in Dutch 'niksnut' or 'nietsnut' loosely translates to 'bum'.