Hi @Bob_Smith
This issue was solved by an user here: Nginx: Increase client_max_body_size
We’re working also in an official way to customize NGINX in the next version 2.16.0
What I recommend to you is to execute OpenVidu normally, and when the nginx container is running, get the file from /etc/nginx/nginx.conf.
Ex:
docker exec openvidu_nginx_1 cat /etc/nginx/nginx.conf
Edit the file and after that apply that replace the original file using a volume as explained in the solution:
volumes:
            ...
            - ./nginx.conf:/etc/nginx/nginx.conf
            ...
This nginx.conf file can override all the rules in /etc/nginx/conf.d/default.conf, just redefine the rules in /etc/nginx/nginx.conf