gistfile1.txt

Foos-iMac:~ foo$ nix --version
nix (Nix) 2.0.4

gistfile2.txt

Foos-iMac:~ foo$ which nix
/nix/var/nix/profiles/default/bin/nix

gistfile3.txt

Foos-iMac:~ foo$ ls -la /Library/LaunchDaemons/org.nixos.nix-daemon.plist
lrwxr-xr-x  1 root  wheel  78 May  8 20:02 /Library/LaunchDaemons/org.nixos.nix-daemon.plist -> /nix/var/nix/profiles/default/Library/LaunchDaemons/org.nixos.nix-daemon.plist

gistfile4.txt

Foos-iMac:~ foo$ cat /Library/LaunchDaemons/org.nixos.nix-daemon.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>org.nixos.nix-daemon</string>
    <key>KeepAlive</key>
    <true/>
    <key>RunAtLoad</key>
    <true/>
    <key>Program</key>
    <string>/nix/store/771l8i0mz4c8kry8cz3sz8rr3alalckg-nix-2.0.4/bin/nix-daemon</string>
    <key>StandardErrorPath</key>
    <string>/var/log/nix-daemon.log</string>
    <key>StandardOutPath</key>
    <string>/dev/null</string>
  </dict>
</plist>