You need to add a server
entry in your Nginx config file for each service. For example, with two hidden services your config file might look something like:
server {
listen 127.0.0.1:<port_hidden_service_1>;
root /path/to/hidden_service_1/;
index_1 index_1.html index_1.htm;
server_name domain_1.onion;
}
server {
listen 127.0.0.1:<port_hidden_service_2>;
root /path/to/hidden_service_2/;
index_2 index_2.html index_2.htm;
server_name domain_2.onion;
}
You might have some additional config fields in there, but you get the idea.
For reference, see the Nginx server name config documentation.