nsg.dns.jp has no CNAME records.
Question and response
Question
dig nsg.dns.jp. NS
Answer
The response has no answer records.
Authority
dns.jp. 1876 SOA z.dns.jp. root.dns.jp. 2025032601 3600 900 1814400 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0