Nix, the language? It's very good for derivations (big, composed k:v maps), but it doesn't feel like a lisp, nor would I want to try using it for docker-compose or a config for pre-commit or an omega one description of an ML model parameterisation.

Then again I'd love to be shown that this partially-considered opinion is wrong.

(Also, isn't Nix's inadequacy as a lisp one of the reasons for the existence of Guix?)