That's not how you use IF and you can't use IF in a menu like that anyhow. You'll need to use $iif and the correct format. You should also format your actions in the menu with the correct format even if it works the way you did it.
menu nicklist {
$iif($1 ison $chan,Script Name)
.Support Bot
..Accept $1's help request:msg botsname .accept $1
}
And because you're already verifying $1, there's no need for $$1 and $N items don't need $+ to connect them to a non-number item.
EDIT: Horstl beat me to it. : )