Technical Question about CNAME and nameservers

Step 1: DNS servers are assigned to a domain. Step 2: Domain zone is created on these DNS servers. It can contain records of different types (A, NS, MX, CNAME, etc).

So, CNAME records cannot override DNS. As they are part of DNS.

Or, did I misunderstand the question? If you can give an example what you need to setup (or tried to setup with some error shown), it would be easier to answer

Your nameservers take precedence, assuming you're referencing:

NS1.Example.com
NS2.Example.com

Also, as per rfc1912:

(quote begin)
A CNAME record is not allowed to coexist with any other data. In other words, if suzy.podunk.xx is an alias for sue.podunk.xx, you can't also have an MX record for suzy.podunk.edu, or an A record, or even a TXT record. Especially do not try to combine CNAMEs and NS records like this!:

podunk.xx. IN NS ns1
IN NS ns2
IN CNAME mary
mary IN A 1.2.3.4

This is often attempted by inexperienced administrators as an obvious way to allow your domain name to also be a host. However, DNS servers like BIND will see the CNAME and refuse to add any other resources for that name. Since no other records are allowed to coexist with a CNAME, the NS entries are ignored. Therefore all the hosts in the podunk.xx domain are ignored as well!

(quote end)

The above quote refers to NS records (without D) processed by DNS server(s)

Thank you guys! That answers my question.