Hi @Peter_Sabbagh,
As a workaround, you could configure NordVPN itself as a pathway for the Core to reach ARC, in place of port forwarding. While this isn’t an officially supported means of streaming via ARC, users have generally found success by following the steps over in our #tinkering category. I suggess you have a look around over there. Here’s an example thread: VPN: step-by-step
I also recommend looking into TailScale, a more robust proxy solution: Tailscale implementation with ARC to circumnavigate ISP CGNAT
These unofficial workarounds might get ARC running for you.