oneinstack/config/opencart.conf

location = /sitemap.xml {
  rewrite ^(.*)$ /index.php?route=feed/google_sitemap break;
}
location = /googlebase.xml {
  rewrite ^(.*)$ /index.php?route=feed/google_base break;
}
location / {
  # This try_files directive is used to enable SEO-friendly URLs for OpenCart
  try_files $uri $uri/ @opencart;
}
location @opencart {
  rewrite ^/(.+)$ /index.php?_route_=$1 last;
}