Apex domains cannot have CNAME records.
Question and response
Question
dig minsal.cl. NS
Answer
minsal.cl. 4 NS ns3.minsal.cl.
minsal.cl. 4 NS ns.minsal.cl.
minsal.cl. 4 NS ns2.minsal.cl.
minsal.cl. 4 NS secundario.nic.cl.
Authority
The response has no authority records.
Additional
ns.minsal.cl. 4 A 200.29.130.138
ns2.minsal.cl. 4 A 163.247.122.56
ns3.minsal.cl. 4 A 200.29.130.11
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0