Apex domains cannot have CNAME records.
Question and response
Question
dig us-gov-west-1.compute.amazonaws.com. NS
Answer
us-gov-west-1.compute.amazonaws.com. 5 NS ns-1161.awsdns-17.org.
us-gov-west-1.compute.amazonaws.com. 5 NS ns-61.awsdns-07.com.
us-gov-west-1.compute.amazonaws.com. 5 NS ns-930.awsdns-52.net.
us-gov-west-1.compute.amazonaws.com. 5 NS ns-1597.awsdns-07.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0