on $*:TEXT:/^[!@.]Setpcw/Si:#: {
  if ($2 !isnum) || ($2 > 170) || ($3 != $null) || ($2 == $null) { notice $nick you need to select a PC world between 1-170 | halt
  }
  if ($nick isop $chan) || ($nick ishop $chan) {
    set %pcw [ $+ [ $chan ] ] $2
    set %pcsetter [ $+ [ $chan ] ] $nick
    set %pcwtime [ $+ [ $chan ] ] $ctime
    msg $chan 14[ 4PEST CONTROL 14]: The Pest Control World has changed! Type 4!Pcw14 to view it!
  }
  else notice $nick Sorry, you need Op or Half-Op to set a PCW!
}
on $*:TEXT:/^[!@.]Pcw/Si:#: {
  var %pc $iif($left($1,1) == @,msg $chan,notice $nick)
  if (%pcw [ $+ [ $chan ] ] == $null) {
    notice $nick There is no PCW set for this channel! | halt
  }
  else %pc 14[ 4PEST CONTROL 14]: The current 4PCW14 for $chan is4 %pcw [ $+ [ $chan ] ]  14set by4 %pcsetter [ $+ [ $chan ] ] 14|4 $duration($calc($ctime - %pcwtime [ $+ [ $chan ] ] )) 14ago.

}

if ($2 !isnum) || ($2 > 170) || ($3 != $null) || ($2 == $null) { blah }
could be shortened to
if ($2 !isnum 1-170) { blah }

if (%pcw [ $+ [ $chan ] ] == $null) {
could be
if (!%pcw [ $+ [ $chan ] ]) {

on $*:TEXT:/^[!@.]Setpcw/Si:#: {
  if ($2 !isnum 1-170) { notice $nick you need to select a PC world between 1-170 | halt
  }
  if ($nick isop $chan || $nick ishop $chan) {
    set %pcw [ $+ [ $chan ] ] $2
    set %pcsetter [ $+ [ $chan ] ] $nick
    set %pcwtime [ $+ [ $chan ] ] $ctime
    msg $chan 14[ 4PEST CONTROL 14]: The Pest Control World has changed! Type 4!Pcw14 to view it!
  }
  else notice $nick Sorry, you need Op or Half-Op to set a PCW!
}
on $*:TEXT:/^[!@.]Pcw/Si:#: {
  var %pc $iif($left($1,1) == @,msg $chan,notice $nick)
  if (!%pcw [ $+ [ $chan ] ]) {
    notice $nick There is no PCW set for this channel! If you wish to set one you can type !setpcw 1-170. | halt
  }
  else {
%pc 14[ 4PEST CONTROL 14]: The current 4PCW14 for $chan is4 %pcw [ $+ [ $chan ] ]  14set by4 %pcsetter [ $+ [ $chan ] ] 14|4 $duration($calc($ctime - %pcwtime [ $+ [ $chan ] ] )) 14ago.
}
}