This script will replace a person's nick with another of your choosing, which usually isn't recommended, but can help with avoiding confusion of people changing nicks all the time.
usage:
right click a name to add a nickname
(if it displays the text in a way your mirc doesn't usually, like timestamps and such, just go into the script and delete the part that adds the time stamp).
Eventually, i'll have it add by nickname and ip address or mask or v host.
Have fun.
updates: more feedback when you make an action
YOU MUST RESTART MIRC AFTER LOADING THIS SCRIPT, OR IF YOU ARE LAZY TYPE THIS INSTEAD:
/hmake nickc 100
you only need to type that the first time you run it, after you restart mirc the next time, you will never need to do this again.

menu nicklist {
  .nicknames
  ..add: { hadd nickc $1 $?="what should their nickname be?" | hsave nickc nickc.txt | echo -a  $hget(nickc,$1) is now the nickname for $1 : $hget(nickc,0).item Nicknames Total }
  ..del: { hdel nickc $1 | hsave nickc nickc.txt | echo -a  $1 no longer has any nickname set : $hget(nickc,0).item Nicknames Total }
  ..clear: { hfree nickc | hmake nickc 100 | hsave nickc nickc.txt | echo -a Nicknames list cleared. }
}
on ^*:text:*:*: if ($hget(nickc,$nick)) { var %nickpo $mid($nick($chan,$nick).pnick,1,1) | haltdef | echo $iif($chan,$chan,$nick) $+([,$gettok($time,1-2,58),]) $+(<,$iif($istok(@ % ~ &,$mid($nick($chan,$nick).pnick,1,1),32),$mid($nick($chan,$nick).pnick,1,1),$null),$hget(nickc,$nick),>) $1- }
on *:start: { hmake nickc 100 | hload nickc nickc.txt }
on ^*:action:*:*: if ($hget(nickc,$nick)) { var %nickpo $mid($nick($chan,$nick).pnick,1,1) | haltdef | echo $iif($chan,$chan,$nick) $+([,$gettok($time,1-2,58),]) $+(*,$chr(32),$iif($istok(@ % ~ &,$mid($nick($chan,$nick).pnick,1,1),32),$mid($nick($chan,$nick).pnick,1,1),$null),$hget(nickc,$nick)) $1- }