Nginx as Reverse Proxy – Setup for Multiple Domains & Hosts

This question has probably been asked several times, but with all results I can find and my little knowledge, I'm kind of lost. I'm using Fedora 29.

What I try to do with nginx :

• Use one let's encrypt ssl certificate with several domain names
• map each domain to a particular internal host (DNS or IP in config file, I don't mind, whatever will work)
• all hosts use ssl internally already (no http available – several listening ports)
• if you use http from the outside, I would like to have a redirection to https

Sample :

• application.domain.com –> https://hostname1.domain.local (or IP 1)

• test.domain.com –> https://hostname2.domain.local:1234 (or IP 2)

• www.domain.com –> https://hostname3.domain.local (or IP 3)
  etc…

How would I be able to do that? Let's encrypt configured me the nginx config automatically but it seems a bit too much.

Many thanks for the answer, I feel I get some progress, even if not working for the moment.
I post here my full config file be cause I have now a "502 Bad Gateway" error. The IP is not in the same subnet as the reverse proxy, but fully accessible, no firewall or routing issue.

Any idea where I can look to move forward ? In original config, there is also a certbot conf file that include cyphers and protocols. Maybe I need to re-include it ?

Also : the internal servers I try to access have certificates signed ith my own AD CS, but no root certificate has been installed on the reverse proxy. Maybe I should ?

# For more information on configuration, see:
#   * Official English Documentation: http://nginx.org/en/docs/
#   * Official Russian Documentation: http://nginx.org/ru/docs/

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

# Load dynamic modules. See /usr/share/doc/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 4096;

    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;

    # Load modular configuration files from the /etc/nginx/conf.d directory.
    # See http://nginx.org/en/docs/ngx_core_module.html#include
    # for more information.
    include /etc/nginx/conf.d/*.conf;

    server {
        listen 80;
        server_name  _;
        return 301 https://$host$request_uri;
    }

    server {
        listen  443 ssl;
        server_name scans.domain.com;
        ssl  on;
        ssl_certificate /etc/letsencrypt/live/www.domain.com/fullchain.pem; # managed by Certbot
        ssl_certificate_key /etc/letsencrypt/live/www.domain.com/privkey.pem; # managed by Certbot

        location  / {
                proxy_pass  https://192.168.XX.YY/;
        }
    }
}