Use this link to find the best server from your location. Best to disconnect the VPN via the desktop client first.
https://nordvpn.com/servers/tools/
Pick the country you want. You can pick a security protocol in the advanced settings link, but the default is wireguard, which should be OK.
Once it has determined the best server, copy the server number and go back to the desktop client and paste the server number into the search box. Click connect. All you need is the first part of the address, for example, US 1234.
Sometimes happens that a NordVPN address is banned, but there's a lot to choose from.
The NordVPN client is pretty robust, I would use that rather than a browser add on.