Hello M B 5747,
This can be frustrating. My first thought is to check whether you may have "double NAT", which would require setting up two levels of port forwarding (one in each NAT firewall). To check that, start with comparing your Nest WiFi Router's WAN IP address (in the Google Home app – tap your Nest WiFi Router, then the gear icon in the upper right corner; the WAN IP address will be in the block titled "Wi-Fi information") to what the outside world sees as your public IP address (I just do a Google search for "what's my IP address", and pick one of the results to see what the world thinks my public IP address is).
If these two addresses don't match, you have another NAT firewall outside your Nest WiFi system. You'll need to configure that system to port forward from the actual public IP address to your Nest WiFi Router's WAN IP address. Then, the Nest WiFi Router port forward should deliver incoming connections to your minecraft server.
If you don't have double NAT, then I would continue to focus on your server. I run minecraft on an older iMac, and I had no trouble making this work. If you're running it on a Windows machine, I'm afraid I can't provide much help. Do be aware that if you are connecting your server via either Ethernet or WiFi, the Google Nest WiFi system will see those as two different devices and will assign different IP addresses to them. So, pick one connection method and stick with it.
From: MichaelP
(Gold Product Expert)
