Here, for anyone needing to host a D6 LTS site, is a working Nginx fragment (tested with Nginx 1.10.3).
You can reuse your standard Drupal 8 config for everything else (e.g. images, protecting private files and so on).
# Drupal 6 LTS index index.php; location / { if (!-e $request_filename) { rewrite ^/(.*)$ /index.php?q=$1 last; } }
Ordinarily, for modern Drupal sites, I’d use the following standard try_files statement, but I couldn’t get it serve D6 subpages correctl (it just redirects to the homepage, even with the q=… added – email me if you know why).
# Drupal 8 location / { try_files $uri /index.php?$query_string; }