Problem here is your domain or sub domain run on port 80. And if you run node app on let say 5000 port you need to configure nginx.(bind 80 to 5000)
It's better you create sub domain for each node app.
But the still catch is you can't run it manually from terminal as there is already port 80...
I am running node application on port 80 and a sub domain which is running on port 80.
If I run using node.js run application it works but the stdout was not able to trade it was not captured in error_log my application generate verbose output I need to read that
I install pm2 and disabled...
it is showing following files which of the files are required documentation shows it required .cert and .pem
cert.pem
chain.pem
fullchain.pem
privkey.pem