Sorry, I assumed since you already knew to check the mirc help first that you were comfortable with this stuff.
mIRC user lists can be a little tricky. I don't really use them so I don't understand when it adds wildcards and when it doesn't.
If you ignore by nickname:
it will probably get added this way: nickname!*@*
So you cannot just search for the nick, you have to match:
$ignore(0) = total in the ignore list.
$ignore(1) = 1st in ignore list
$ignore($address($nick,3)) will return the mask ($true) if it matches.
Basically, decide how you want to set the ignore. Set it, then see how mIRC sets it by looking at $ignore(1). ( //echo -a $ignore(1) )
You will have to match this style, so if mIRC adds a * wildcard to the front of it, you will have to add it as well to match.
THANKS FOR CHECKING THE HELP FILE FIRST!