First fix permissions causing the error:
sudo chown -R "$(whoami)":admin /usr/local
On macOS Mojave, the chown command needs to be run on the specific directory, an example for the permissions issue in /usr/local/lib directory, this command would be
sudo chown -R "$(whoami)":admin /usr/local/lib
Then relink node with the --force option as directed:
brew link --overwrite node