CBT Nuggets Question on DNS Part 1

Was watching Part 1 of DNS and noticed that James configured a DNS server to host the zone cbtnuggets.com
Where did nuggetlabs.com come from all of a sudden?
:
Where did nuggetlabs.com come from all of a sudden?

Comments
Ok what James did was configure a DNS server (without AD). His zone was called "cbtnuggets.com"
After watching his screen and looking at the SOA and NS record for the configured zone, it shows "dcnugget3.nuggetlab.com"
Where the heck did he get nuggetlab.com from? The configured zone in the first place was "cbtnuggets.com"
I attempted to follow his same steps at least what he did on screen...
SOA Record- [1], labserver1., hostmaster.
NS- labserver1.
Well substitute labserver1 for dcnugget3. Forgot to rename my machine.
My TCP/IP setings is:
IP- 172.16.0.2
DNS- 172.16.0.2
I hate it when he installs stuff without you physically seeing it. Kind of throws me off.