alt Hacker NewsNix isn't a scripting language in the sense you seem to have in mind. The snippets you saw that looked like Bash most likely were literally Bash, embedded as multiline strings in Nix.
Nix doesn't have much in common with Haskell.
Nix is a really small language, and you can learn pretty much all of it in a few minutes: https://nixcloud.io/tour/?id=introduction/nix
Nix is awesome and has not been part of any pendulum (or clock). It's complex enough that it allows you to build programs with it, but on such a simple core that for all intents and purposes it is a config language.