My apologies if this is against the rules to post an answer to your own question, but many times in the past I’d wished others had done the same.

For those that weren’t aware, whenever you use docker-compose up, it automatically creates a default docker network if you don’t specify any in the docker-compose.yaml. Docker containers in the same network automatically get a DNS entry created for the container name. That means you can access the other containers in the network using something like http://mycontainername:8080.

For the Nginx container running the reverse proxy, the proxy_pass value ended up just being http://myapp:3000.

Definitely seems like a no-brainer. I know I had seen posts online regarding using a name url like that but was ignoring all them because I didn’t realize the docker network was doing that behind the scenes and din’t put it together that using the container name would work in this way.

Hopefully this helps someone!