Sorry, Jethro_, the reason I said you might as well check $nick == NickHere is because the code you suggested was no more secure than that. If you are comparing the current address of the person triggering the event (nick!ident@host) against, for example, $address(NickHere,2), the script will be comparing the triggered address with the address of whoever is currently using NickHere.
With that being the case, anyone using NickHere would validate correctly as the desired person.