SlackBuildsOrg/network/nordvpn

The NordVPN app for Linux protects your sensitive data with
military-grade encryption, so that whatever you do online stays secure
and private.
More than 5000 servers worldwide. No logs of your online activity.
Secure up to 6 devices with a single account.
Access online content securely, with no restrictions.

This script requires a 'nordvpn' group to exist before running.
You can create this group like this (Run these as root):
    groupadd -g 373 nordvpn
    usermod -aG nordvpn $USER (Replace $USER with your username)
Then log out of the system and login again.

The following can be used to start/stop NordVPN automatically:
/etc/rc.d/rc.local
  if [ -x /etc/rc.d/rc.nordvpn ]; then
    /etc/rc.d/rc.nordvpn start
  fi

/etc/rc.d/rc.local_shutdown
  if [ -x /etc/rc.d/rc.nordvpn ]; then
    /etc/rc.d/rc.nordvpn stop
  fi

NOTE: NordVPN has implemented NordLynx (WireGuard protocol) into the
app. Dependencies already satisfied at full install.
In case of any issue, you need to reinstall following packages:

wireguard-linux-compat
wireguard-tools

Then you can switch to NordLynx with the following command:
'nordvpn set technology NordLynx'

And connect using:
'nordvpn c'

You can always switch back to OpenVPN using this command:
'nordvpn set technology OpenVPN'