Apex domains cannot have CNAME records.
Question and response
Question
dig nova.is. NS
Answer
nova.is. 5 NS zariyah.ns.cloudflare.com.
nova.is. 5 NS patrick.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0