As I mentioned in previous post, you can restrict an event to only 1 nick by adding a line checking if $nick was the approved nick. This example lets you list more than 1 approved nick, and ignores anyone who is not an exact match:

on @*:text:!open:#: {
  if ($istok(aribun21 aribun21 aribun21,$nick,32)) return
  if (%list.status != closed) { msg $chan The list is already open | return }
  unset %list.status
  msg $chan OK $chan the list is now open!

You can change any of the duplicate aribun21 to another approved nick, as well as adding another nick within that list, as long as each nick is separated from each other by a space character. This is exactly the same as the current !open trigger except for the extra line, which you can also copy to the !close event too.