If you have a reseller account you may want to use your own name servers with your customers domains instead of ours.
Once you log in to WHM, on the left menu click "Basic cPanel & WHM Setup".
You can now edit the name servers for your reseller plan, you should enter at least two name servers here. Click save changes and now any new domains added to your plan will use your name servers.
If you haven't already you should now set up your name servers in DNS and officially register them with your domain registrar.