Hello,
I've ample of setting up server. As per your requirements you need to get nginx configured to support ssl and you want emails to support ssl, basically nginx and emails are different things, nginx works for web and postfix,dovcot are to be configured for emails. I can make both support the ssl certificate, before proceeding ahead I would like to know you server configurations.
We can have further discussion over the exact requirements and my experience over message.
Thanks