OK, I've tested it, and unfortunately while it works to activate the vpn service, it exhibits the same issues as when I tried installing it on one of my Arch-based distros via the install script provided on the github page (with extra tweaking required to get the script to work).
Problems (same as my trial in the other distro):
1. The initial login into your Nordvpn account works fine. However, when you first choose a server to connect to, a dialogue opens asking for your sudo password so that IPV6 will be disabled. I have no idea why I would need to disable IPV6 since none of the other ways of connecting to Nord - the installable client from the company itself (in MXPI), entering a .ovpn profile into Network Manager, and the Nordvpn Firefox Add-on - required sudo password or indicated that IPV6 was disabled. And the writeup in the github page specifically says no elevated permission is required.
So I just clicked on "login" or "cancel" button in the password dialogue without entering my sudo password. And lo and behold, it proceeds in any case to connect to the VPN server chosen. I checked by going to Nordvpn's home page, which detects whether you are using vpn or not.
ksnip_20210218-125859.png
2. once connected, the "disconnect" button doesn't work to disconnect vpn. You continue to be connected. I checked with Nord's home page.
3. WHen I choose a different country's server, the display indicated it's "connecting..."
connected, and then you do get a pop up notification in XFCE that you've connected (again). However I'm not sure whether you are still on the original server or it has indeed switched to a new one. The Nord homepage display tells me I'm still protected BUT the same VPN IP address and ISP name from before is displayed. That may or may not indicate that the user is still connected to the first server originally connected to; I don't really know.
I'm not sure whether the bugginess is because - as Swamprabbit pointed out - the developer did say he's no longer developing/updating it because he stopped using Nord himself.
It is a useful GUI though, that displays every single server available in each country, and ranks them from lowest current load to heaviest load. You can choose which particular server you wish to connect to in whatever country is selected.
I'll keep it in this particular install of MX19, but I think for my other 2, I'll stick to using the CLI commands + Nordvpn client that is installable from MXPI Popular apps.
Thanks for packaging this anyway, SwampRabbit. I do appreciate it.