nginx and node js server with ssl - node.js

Question

const https = require(`https`);
const fs = require(`fs`);
const options = {
key: fs.readFileSync(...),
cert: fs.readFileSync(...)
};
https.createServer(options, app).listen(8000);
My node js server looks like this.
does it mean I have to configure nginx like this?
location / {
proxy_pass https://localhost:8000/;
}
Not, proxy_pass to http://localhost:8000/
what makes me confused is that I think network inside the server does'n need ssl.
https server on application server also needs ssl configuration on nginx, right?
I also tried app.listen instead of https.createServer.
My node js app and nginx configuration looks like this.
app.listen(4416);
server {
listen 443 ssl default_server;
listen [::]:443 ssl default_server;
server_name _;
root /root/app;
index template.html;
ssl_certificate ...;
ssl_certificate_key ...;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
location / {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_pass http://localhost:4416/;
proxy_buffering off;
proxy_read_timeout 90;
#websocket support
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
}
server{
listen 80;
listen [::]:80;
return 301 https://$host$request_uri;
return 404;
}
In this case, redirection keeps incurred, and I don't know the reason why. What did I miss?
If I did https.createServer(SSL_OPTION, app).listen(4416) instead of app.listen(4416), it doesn't have a connection at all. And if I fix nginx configuration proxy_pass to https://localhost:4416;, then it works well. Things are done well but, I wonder why this is happening.