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.
I tend to write JavaScript that looks a bit like Nix... but in general, the imperative constructs aren't suitable to the lazy evaluation strategy of Nix.