Finally fixing my nix-based dev env on MacOS. I was getting error: tool 'git' not found when in a dev env.
sudo xcode-select --reset
sudo xcode-select --switch /Library/Developer/CommandLineTools
wound up fixing it
sudo launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist worked for me when I updated MacOS and needed to reboot. Thanks Dan!