> But I'd like a way to install it on user machines, users who probably don't want to install Nix just for my thing. Nix probably doesn't have a way to make self contained packages, right?

I mean... That's the heart of the problem right there. You can either have all statically compiled binaries (which don't need Nix to run) which have no outside dependencies but result in a ton of wasted disk space with duplicate dependency data everywhere, or you can share dependencies via a scheme, of which the only one that makes real sense (because it creates real isolation between projects but also lets you share equal dependencies with zero conflicts) is Nix's (all of the others have flaws and nondeterminism).