Something not mentioned here is that each and every single macOS update will break your Nix install too. This is, by far, the most frustrating part of using Nix on macOS.
The only things that broke for me after the update were the xcode command-line tools, which break for everyone[1].
[1](https://stackoverflow.com/questions/32893412/command-line-to...)
They bothered writing a system capable of dropping the conflicted file in Relocated Items for us to optionally use--but they appear to be only using it for /etc/bashrc, and not /etc/zshrc. So, people who use zsh by choice or default get dumped on a bit :/
Some background in https://github.com/NixOS/nix/issues/3616
Does anyone know if this update was a fluke?