Clearly a /notice $nick command sends it to the $nick directly, whereas a /msg $chan sends it to the entire channel.
There's always /msg $nick too.
In anyevent, you can't use $chann or $chann!!. Try $chan $+ !
Indeed, $chann isn't an identifier, creat a custom one..

alias chann {
return $+($chan,$str($chr(33),2))
}
Which'll return the #mIRC!!
-Andy