When you recieve the ctcp, set a variable to store $nick. e.g. %ctcpnick
Code:
on *:input:*:if $active == Message Window { .timer 1 0 editbox -ap /ctcp [color:green]%ctcpnick[/color] }
on *:active:*:if $active == Message Window { editbox -ap /ctcp [color:green]%ctcpnick[/color] }