Apex domains cannot have CNAME records.
Question and response
Question
dig niig.com.np. NS
Answer
niig.com.np. 5 NS dns1.niig.com.np.
niig.com.np. 5 NS tilicho.subisu.net.np.
Authority
The response has no authority records.
Additional
dns1.niig.com.np. 5 A 202.51.75.72
tilicho.subisu.net.np. 5 A 202.63.240.3
tilicho.subisu.net.np. 5 AAAA 2403:3800:200:0:0:0:0:3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0