No, Nix syntax is much nicer than Javascript. Consider, for example, the similarity between a let expression and an attribute set (NOT JSON by the way):

  let
    foo = 42;
    bar = "a string";
  in {
    baz = "deja";
    quux = "vu";
  }

Javascript:

  const foo = 42;
  const bar = "a string";
  return {
    baz: "similar",
    quux: "but different"
  };

You find this kind of thing all over the place. Nix is a much smaller and simpler language syntactically, and more pleasant to write.