Yeah, that sounds like a GPT-3.5 problem to me. I wouldn't trust 3.5 to write me an Nginx config, but I'd give 4 a shot at it.
I just tried using GPT-4 to translate a random htaccess file I found to nginx and it seemed to do a good initial job: https://gist.github.com/simonw/8174f653a0c08c120830c56332054...