How to allow SSH into Terminal after connecting to VPN server using NordVPN servers through OpenVPN?

When using the NordVPN Linux client, iptables are used to change traffic instead of modifying the routes. To allow SSH to go through, you need to whitelist the SSH port.

nordvpn whitelist add port 22

I were able to find a solution for my issue by:

when you connect to the Server by its public IP address, the return packets get routed over the VPN. You need to force these packets to be routed over the public eth0 interface. These route commands should do the trick:

ip rule add from x.x.x.x table 128
ip route add table 128 to y.y.y.y/y dev eth0
ip route add table 128 default via z.z.z.z

Where x.x.x.x is your Server public IP, y.y.y.y/y should be the subnet of your Server public IP address, eth0 should be your Server public Ethernet interface, and z.z.z.z should be the default gateway.