This assumes you have already install NordVPN on one of your Linux servers.

Enable meshnet.

nordvpn set meshnet on

Optionally, let's give our Linux server running NordVPN a nickname.

nordvpn meshnet set nickname my-nordvpn-server

Let's get the list of devices that have been added to our NodeVPN mesh net.

~]$ nordvpn meshnet peer list
This device:
Hostname: john.doe-himalayas.nord
Nickname: my-nordvpn-server
IP: 10.11.12.13
Public Key: abCDefGHijkLMdnoQRStuvWxyZ123456789=
OS: linux
Distribution: Amazon Linux

Local Peers:
Hostname: john.doe-everest.nord
Nickname: dads-phone
Status: connected
IP: 10.11.12.13
Public Key: abCDefGHijkLMdnoQRStuvWxyZ123456789=
OS: android
Distribution: 34
Allow Incoming Traffic: enabled
Allow Routing: disabled
Allow Local Network Access: disabled
Allow Sending Files: enabled
Allows Incoming Traffic: enabled
Allows Routing: disabled
Allows Local Network Access: disabled
Allows Sending Files: enabled
Accept Fileshare Automatically: disabled

Let's allow one or more peers to use our Linux server running NordVPN as the NordVPN host server.

nordvpn meshnet peer routing allow <hostname or IP address of the peer>

Configure a peer device to your Linux server running NordVPN as the NordVPN host server. On the Linux server running NordVPN, there should be an interface named nordlynx.

~]$ ip address show nordlynx
3: nordlynx: <POINTOPOINT,UP,LOWER_UP> mtu 8921 qdisc noqueue state UNKNOWN group default qlen 1000
    link/none
    inet 100.102.103.104/10 scope global nordlynx
       valid_lft forever preferred_lft forever

tcpdump can be used to confirm that traffic from your device that has been configured to use your Linux server running NordVPN as the NordVPN host server is routing through your Linux server.

~]# tcpdump --interface nordlynx
12:05:07.824817 IP my-phone > my-nordvpn-server: ICMP echo request, id 36566, seq 0, length 64
12:05:07.824850 IP my-nordvpn-server > my-phone: ICMP echo reply, id 36566, seq 0, length 64