nslookup gives those results for me for other domains too - not just this one in this thread. I usually use dig so don't know what it normally does but doesn't seem off to me.
Checking some of the well-known domains on the net...
It seems about 50/50 that will return a SOA record for an FQDN/subdomain that doesn't exist. nslookup -q=soa not.a.real.name.or.zone.EXAMPLE.COM
[replacing EXAMPLE.COM with FB, IG, Twitter, Google, IBM, MS, etc.]