Secure ssl configure for Nginx

nginx.conf

user  nobody;
 
worker_processes  2;
 
#error_log   /dev/null crit;
 
events {
    worker_connections  1024;
}
 
http {
    include       mime.types;
    default_type  application/octet-stream;
 
    sendfile        on;
    #tcp_nopush     on;
 
    keepalive_timeout  65;
 
    gzip  on;
 
    expires off;
 
    server_tokens off;
 
    server {
        listen                     80;
        listen                     443 ssl;
        listen                     [::]:80;
        listen                     [::]:443 ssl;
        server_name                example.com;
 
        ssl                        on;
        ssl_certificate            path/to/cert;
        ssl_certificate_key        path/to/key;
 
        ssl_session_cache          shared:SSL:1m;
        ssl_session_timeout        5m;
 
        ssl_protocols              TLSv1.2;
        ssl_ciphers                ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:AES256+EECDH;
        ssl_prefer_server_ciphers  on;
        ssl_ecdh_curve             secp384r1;
 
        ssl_stapling               on;
        ssl_stapling_verify        on;
        resolver                   8.8.8.8 8.8.4.4 valid=300s;
        resolver_timeout           5s;
 
        add_header                 Strict-Transport-Security  max-age=31536000;
 
        error_page 497 @https;
        location @https {
            rewrite ^(.*)$ https://$host$1 permanent;
        }
    }
    
    server {
        listen                     80;
        listen                     443 ssl;
        listen                     [::]:80;
        listen                     [::]:443 ssl;
        server_name                ~^(www\.)(?<domain>.+)$;
        rewrite                    ^(.*)$ https://$domain$1 permanent;
        
        error_page 497 @https;
        location @https {
            rewrite ^(.*)$ https://$host$1 permanent;
        }
    }
}