A quick way to do this is instead of putting "yournick", set a variable... Like %blname (Your Name)
And then change everything from "yournick" to %blname

alias blname {
set %blname $1 
echo -a :: Your BlackList name has been set to $1 :: 
}

Then add in the description to do /blname (Your Name) so the script will work.
It makes things easier :]