october.conf

server {
  listen 80;
  
  index index.php;
  server_name october.cms;

  # root directory
  root /path/to/octobercms;

  location / {
    try_files $uri $uri/ /index.php$is_args$args;
  }
  
  location ~ \.php$ {
    ...
  }
}

project.conf

server {
  listen 80;
  
  index index.php;
  server_name new.project;

  # root directory
  root /path/to/new.project/public;
  
  location / {
    try_files $uri $uri/ /index.php?$query_string;
  }
  
  location /uploads/ {
    # root directory october cms
    root /path/to/octobercms;
  }

  # FOR PHP FILES
  location ~* \.php$ {
    ...
  }
}