Yeah this is a good use case for it, if I remember right you can also trivially generate a live installer iso from the same nix configuration you’d use to run any usual updates. So you can make a custom installer for your exact configuration and copy that onto a flash drive to bootstrap you into a working environment. I think the live installer would generate something like a hardware-configuration.nix too.
That’s sweet, I didn’t think about using nixos-anywhere for this purpose (just simplifying the install process on a new machine). I used it to great success to install NixOS on a VPS that only had a few OS options like Debian.