route different proxy based on subdomain request in nginx

Question

I have one dedicated server in that server I deployed 5 nodejs application.

domain name: www.nnd.com
dedicated server ip: xxx.xx.x.60

I had

Answer 1

create a virtual host for each

server {
  server_name sub1.example.com;
  location / {
    proxy_pass http://127.0.0.1:xxxx;
  }
}
server {
  server_name sub2.example.com;
  location / {
    proxy_pass http://127.0.0.1:xxxx;
  }
}

And go on, change the port number to match the right port.