I do use Nord VPN - no issues
There is two things to remember when using NordVPN
- Nord VPN seems to expect systemd-resolved as resolver
- It also relies on wireguard-tools
A default Manjaro installation uses openresolv - which causes NordVPN to fail when the connection is shutdown.
The aforementioned Arch wiki article links back to [root tip] [How To] NordVPN on Manjaro in the troubleshooting section of NordVPN - ArchWiki