Network Load Balancer with the NGINX Ingress Controller on Amazon EKS always returns a 503 error
In Ingress definition you have specified wrong backend service name: go-hello which is not compatible with service name you created for backend - go-hello-service.
Also for the future you can get a 503 error from nginx when basic-auth is enable in the Ingress and the annotation nginx.ingress.kubernetes.io/auth-secret is referencing a non-existing secret.
You can also add the missing secret or removing all basic-auth annotations from the Ingress can resolve this situation.