locate your webserver root
C:\Bitnami\nginxstack-1.14.0-0\nginx\html\
edit virtual host
C:\Bitnami\nginxstack-1.14.0-0\nginx\conf\bitnami\bitnami-apps-vhosts.conf

server {
listen *:80;
server_name hello.com www.hello.com;
root C:/Bitnami/nginxstack-1.14.0-0/nginx/html/hello.com;
index index.html;
}

server {
listen *:8081;
server_name hello2.com www.hello2.com;
root C:/Bitnami/nginxstack-1.14.0-0/nginx/html/hello2.com;
index index.html;
}

C:\Windows\System32\drivers\etc\hosts
127.0.0.1 localhost hello.com hello2.com

open ports

now you can access hello2.com via yourexample.com:8081
and access hello.com via yourexample.com/hello.com