I'm able to connect to the panel with my internal IP, but can't connect with my external IP.
I port forwarded port 80 and 5656 and am getting the ' Welcome to nginx' page with the external IP
Am I missing something?
This is because of the connection URL that is being used.
Nginx will attempt a best-match rule based on the URL you provide against the server_names. When you installed the panel, you defined the URL (I assume) as your local IP, so Nginx will route that URL to the panel, and anything else to the default server.
You can add those new URL names to the server_name field as well:
server_name 192.168.1.1 www.example.net