You don’t.
You do not use runserver in production.
Quoting directly from the runserver docs:
DO NOT USE THIS SERVER IN A PRODUCTION SETTING.
For what to do, see the references identified at Deployed site not reachable by domain name - #6 by KenWhitesell for information on how to properly configure your project. I can’t be more specific here because the details may vary (slightly) based upon what Linux distro and wsgi container you are using. (You’ve identified one of the variables - you’re using nginx instead of Apache or one of the others.)