Step 1: first create the CSR using the below command: 

openssl req -new -newkey rsa:2048 -nodes -keyout shortz.live.key -out shortz.live.csr

Step 2:  This above command will generate two files in your present working directory, first file                      will be csr and the second one will be the private key file.

Step 3: Generate the SSL certificate using the csr and then upload the ssl certificate on the server and move the ssl certificate and private key in the /etc/nginx/conf.d directory to make the task easy.

Step 4: Then create a ssl configuration file which should be named as like ssl.domain.conf

Step 5 : Ssl configuration file content should be like as below: 

server {

    #listen       8443 ssl http2 ;

    #listen       [::]:8443 ssl;

    listen       443 ssl http2;

    listen       [::]:443 ssl;

    server_name  shortz.live;

    root         /usr/share/nginx/html;

    #access_log  /var/log/nginx/access.globobill.globocom.info.log  main

    access_log  /var/log/nginx/access.ssl.shortz.live.log main;

    ssl_certificate /etc/nginx/conf.d/shortz_live.crt;

    ssl_certificate_key /etc/nginx/conf.d/shortz.live.key;

    ssl_session_cache shared:SSL:1m;

    ssl_session_timeout  10m;

    ssl_ciphers HIGH:!aNULL:!MD5;

    ssl_prefer_server_ciphers on;

    #ssl on;

    charset      utf-8;

    #include /etc/nginx/default.d/*.conf;

        location /mglobopay/ {

                #proxy_read_timeout 300;

                proxy_set_header Host $host;

                proxy_set_header X-Forwarded-Server $host;

                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

                proxy_cookie_path ~*^/.* /;

               #proxy_pass      http://port_http_221;

                #proxy_pass         http://port_http_gc3.1;

        }

        location /app_json {

                             #proxy_set_header X-Real-IP $remote_addr;

                root         /opt/apache-tomcat-8.0.20/webapps/website;

        }

        location / {

                  proxy_set_header X-Real-IP $remote_addr;

                #limit_req_zone $binary_remote_addr zone=mylimit:10m rate=10r/s;

                #proxy_read_timeout 300;

                proxy_set_header Host $host;

                proxy_set_header X-Forwarded-Server $host;

                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

                proxy_cookie_path ~*^/.* /;

               proxy_pass      http://localhost:8080;

               proxy_redirect      http://localhost:8080 https://shortz.live;

               #proxy_pass         http://port_http_gc3.1;

        }

        error_page 404 /404.html;

            location = /40x.html {

        }

        error_page 500 502 503 504 /50x.html;

            location = /50x.html {

        }

}

Step 6: Once you enter all the details in the above file then save the file afterward restart the nginx service.

Step 7: Then you need to make the entry in nginx.conf file for your ssl configuration file as given below: 

  include /etc/nginx/conf.d/timeout.conf;

    #include /etc/nginx/conf.d/*.conf;

    include /etc/nginx/conf.d/ssl.app.globocom.conf;

    include /etc/nginx/conf.d/api1.globocom.info.conf;

    include /etc/nginx/conf.d/api2.globocom.info.conf;

    include /etc/nginx/conf.d/default.conf;

    include /etc/nginx/conf.d/app.globocom.info.conf;

    include /etc/nginx/conf.d/globobill1.globocom.info.conf;

    include /etc/nginx/conf.d/kz.wap1.globocom.info.conf;

    include /etc/nginx/conf.d/wap1.globocom.info.conf;

    include /etc/nginx/conf.d/ssl.globobill.globocom.conf;

    include /etc/nginx/conf.d/globoapps.in.conf;

    include /etc/nginx/conf.d/api3.globocom.info.conf;

    include /etc/nginx/conf.d/ssl.shortz.conf;

    #include /etc/nginx/conf.d/monitoringservice.globocom.info.conf;

    #include /etc/nginx/conf.d/rabbitmq.conf;

   #include /etc/nginx/conf.d/ssl.shortz.conf;

Step 8: Now restart the nginx and check while ssl should be running.

Thank You :)