Nginx elb configuration with proxy-protocol enable. ELB doesn't support websocket at layer 7. So, we need to configure it at TCP layer

nginx_site_config

log_format elb_log '$proxy_protocol_addr - $remote_user [$time_local] ' '"$request" $status $body_bytes_sent "$http_referer" ' '"$http_user_agent"';

server {
    listen 80 proxy_protocol;
    listen [::]:80  proxy_protocol;
    server_name localhost;
    access_log  /var/log/nginx/elb-access_http.log elb_log;
    location / {
      root   /var/www/html;
      rewrite ^(.*)$ https://$host$1 permanent;
      index  index*.html index.htm;
    }
}
server {  
  listen 443 proxy_protocol  ssl;
  listen [::]:443 proxy_protocol  ssl;
  server_name localhost;
  access_log /var/log/nginx/elb-access_https.log elb_log;

  ssl on;
  ssl_certificate /etc/nginx/ssl/cert.crt;
  ssl_certificate_key /etc/nginx/ssl/cert.key;

  root /var/www/html;
  index index.html index.htm index.nginx-debian.html;
  location / {
    try_files $uri $uri/ =404;
  }
}

At ELB Side we need to make following changes.
ElB will be used as a passthrough. Packets are secured as traffic falling at our backends will have ssl enabled with valid certificates.

healthcheck:

TCP:443

Listeners:

Load Balancer Protocol   | Load Balancer Port |  Instance Protocol  | Instance Port  | Cipher |  SSL Certificate
TCP    |    80  | TCP|  80  |  N/A  |   N/A
TCP  |  443 |   TCP |  443   |  N/A |   N/A