Single Nginx Docker vs Multiple Nginx Docker for websites

Not a stupid question, but let's clarify, no matter how you configure nginx and docker, one host IP can only bind one service to one port, so if you want to handle multiple websites on one IP address on port 80/443 (http/https) you would only be able to run ONE nginx container to handle routing between different hostnames (virtual hosts) and redirect traffic to their appropriate backend.

You will also need to either expose these backends on different ports or share the same docker network.

Something you may want to consider is an alternative to the stock nginx container with something more geared to more dynamic backends like Traefik or nginx-proxy