I don't understand why you're forcing the nick to be indented, but aside from that, this worked for me
Code:
echo -ti16 # $str($chr(160),$calc(10-$len($nick))) $+(<,$left($remove($nick(#,$nick).pnick,$nick),1),$nick,>) $1- | halt
It's not much shorter, but it does account for any combinations that you currently have, as well as any other combinations that you're not checking for (eg: ~&@%+)