Thanks for sharing... here is a quick edit

on *:TEXT:!DiceGame*:#: {
  if (($2 !isnum) || ($3 !isnum) || ($4 == $nick) || ($4 !ison $chan)) { .notice $nick You need someone to play against! | return }
  var %DiceGameRolled 1 | var %DiceGameAdded 1
  ;*** Rolls
  while (%DiceGameRolled <= $2) { var %DiceGamePlayer1 $instok(%DiceGamePlayer1,$rand(1,$3),%DiceGameRolled,32) | var %DiceGamePlayer2 $instok(%DiceGamePlayer2,$rand(1,$3),%DiceGameRolled,32) | inc %DiceGameRolled }
  ;*** Total
  while (%DiceGameAdded <= $2) { var %RollTime $gettok(%DiceGamePlayer1,%DiceGameAdded,32) | var %RollTotalPlayer1 $calc(%RollTotalPlayer1 +%RollTime) | var %RollTime $gettok(%DiceGamePlayer2,%DiceGameAdded,32) | var %RollTotalPlayer2 $calc(%RollTotalPlayer2 +%RollTime) | inc %DiceGameAdded }
  msg # $+([,$mNiCK($nick) vs. $mNiCK($4),]) Dice roll with $mNUM($2) $+(15,$chr(40),,$mNUM($3),-SiDED15,$chr(41),) $+(dice,$iif($2 > 1,s),...) $&
    $mNiCK($iif(%DiceGamePlayer1 > %DiceGamePlayer2,$nick,$4)) is the winner... rolled $iif(%RollTotalPlayer1 > %RollTotalPlayer2,%DiceGamePlayer1 $+(15,$chr(40),,$v1,15,,$chr(41),) vs. %DiceGamePlayer2 $+(15,$chr(40),,$v2,15,,$chr(41),),%DiceGamePlayer2 $+(15,$chr(40),,$v2,15,,$chr(41),) vs. %DiceGamePlayer1 $+(15,$chr(40),,$v1,15,,$chr(41),))
}