mx.nixins.com has no NS records.
NS records for this zone are defined at nixins.com.
NS records for this zone are defined at nixins.com.
Question and response
Question
dig mx.nixins.com. NS
Answer
The response has no answer records.
Authority
nixins.com. 1800 SOA elmo.ns.cloudflare.com. dns.cloudflare.com. 2396760991 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0