nsa5.k8.com.br has no NS records.
NS records for this zone are defined at k8.com.br.
NS records for this zone are defined at k8.com.br.
Question and response
Question
dig nsa5.k8.com.br. NS
Answer
The response has no answer records.
Authority
k8.com.br. 3600 SOA nsa1.k8.com.br. dnsmasters.k8.com.br. 1500 3600 300 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0