(Assuming you are using Anope 2)
If you want all nicks to automatically be killed if the user using them does not identify, you need to edit nickserv.conf line 114:
defaults = "ns_secure ns_private hide_email hide_mask memo_signon memo_receive autoop"
Add to the end of it:
defaults = "ns_secure ns_private hide_email hide_mask memo_signon memo_receive autoop killprotect"
(You can also add kill_quick)
See the help for that on line 94:
* - killprotect: Kill nick if not identified within 60 seconds
* - kill_quick: Kill nick if not identified within 20 seconds, this one overrides the above
* option and the above must be specified with this one
If you just want to enable this feature for your own nick, then just use: (Be identified as this nick)
/msg NickServ SET KILL ON
or
/msg NickServ SET KILL QUICK
If you want to change the times of killprotect or kill_quick, that is found later in nickserv.conf on lines 162 and 163:
killquick = 20s
kill = 60s