That's not the only way. It's definitely the easiest option, but you can also create a temporary fhs environment https://github.com/ElvishJerricco/nixpkgs/commit/05742c15d5a...
That kind of re-emphasizes to me that regardless of the value Nix might offer me, I'm not and probably won't ever be the audience for it, because if it assumes I know that well enough to recognize it by acronym then it's going to assume I know a lot more than that. I can look forward to a few months of Googling and tangents just to get a grip on its fundamentals.
More generally, it seems that the nix documentation (including the reference docs) suffer from not having been developed systematically to introduce things in dependency order.