Trying Nix

uninstall-nix-osx.sh

#!/bin/bash

# !!WARNING!!
# This will DELETE all efforts you have put into configuring nix
# Have a look through everything that gets deleted / copied over

nix-env -e '.*'

rm -rf $HOME/.nix-*
rm -rf $HOME/.config/nixpkgs
rm -rf $HOME/.cache/nix
rm -rf $HOME/.nixpkgs

if [ -L $HOME/Applications ]; then
  rm $HOME/Applications
fi

sudo rm -rf /etc/nix /nix

# Nix wasnt installed using `--daemon`
[ ! -f /Library/LaunchDaemons/org.nixos.nix-daemon.plist ] && exit 0

if [ -f /Library/LaunchDaemons/org.nixos.nix-daemon.plist ]; then
    sudo launchctl unload /Library/LaunchDaemons/org.nixos.nix-daemon.plist
    sudo rm /Library/LaunchDaemons/org.nixos.nix-daemon.plist
fi

if [ -f /etc/profile.backup-before-nix ]; then
    sudo mv /etc/profile.backup-before-nix /etc/profile
fi

if [ -f /etc/bashrc.backup-before-nix ]; then
    sudo mv /etc/bashrc.backup-before-nix /etc/bashrc
fi

if [ -f /etc/zshrc.backup-before-nix ]; then
    sudo mv /etc/zshrc.backup-before-nix /etc/zshrc
fi

USERS=$(sudo dscl . list /Users | grep nixbld)

for USER in $USERS; do
    sudo /usr/bin/dscl . -delete "/Users/$USER"
    sudo /usr/bin/dscl . -delete /Groups/staff GroupMembership $USER;
done

sudo /usr/bin/dscl . -delete "/Groups/nixbld"
sudo rm -rf /var/root/.nix-*
sudo rm -rf /var/root/.cache/nix

# useful for finding hanging links
# $ find . -type l -maxdepth 5 ! -exec test -e {} \; -print 2>/dev/null | xargs -I {} sh -c 'file -b {} | grep nix && echo {}'

Anyone that comes here, just a heads up there are now official docs for uninstalling nix