"familiar syntax"? Perhaps if you use Haskell or ML. That's probably a tie with s-expressions for popular syntax, but definitely not familiar to most people.

I really like nix the package manager and like NixOS the distribution, but learning nix the language was an awful lot of work, and I'm not convinced that it couldn't have been accomplished with a language that is more familiar (Guix demonstrates that baked-in lazy evaluation is not necessary). Even tiny things like "sets" as a name for an associative data type make it just that much harder to learn.