Move from IP to Domain

Before explain how you can do, a small tips: when you want to work on your domain without without having visitors, just edit your computer DNS settings like this : http://www.sordum.org/8266/bluelifehosts-editor-v1-2/

This way you will be the only one to have access to your website during the developement.

But in your case you have to way to do it. By editing the file /etc/nginx/sites-available/1.2.3.4.conf properly to use your domain and to edit also the wordpress settings.

Or to create another wordpress with ee and to move your database and files on it.