You may be getting "domain" and "website" mixed up. If you park the domain at NS, you can then point it anywhere you like. So if your site is hosted at host excellence, you add an A record pointing at the host server ip. If you want to use O365 email, you add an MX record pointed at the 365 mail servers and so on.
Registrar-domain -nameserver _ web site
_ email
_ lync