See if this is your intention:

Code:
on *:TEXT:!pracday:#: {
  /msg $chan Pracday: $iif(%pracday, %pracday [[Set by %pracday.nick $+ ]], Not Set)
}

on *:TEXT:!pracday *:#: {
  /set %pracday $2-
  /set %pracday.nick
  /msg $chan Pracday set: $2- [[Set by $nick $+ ]]
}

-KingTomato