Use e.g. a group arround the on join event:
Code:
#nonsense off
on @*:JOIN:#: {
  ...stuff...
}
#nonsense end


Then, you can add a menu definition to toggle that group:
Code:
menu channel {
  kick nonsense nicks $+($chr(91),$group(#nonsense),$chr(93))
  .$iif(($group(#nonsense) == on),$style(1)) on : .enable #nonsense 
  .$iif(($group(#nonsense) == off),$style(1)) off : .disable #nonsense 
}