CHOCONOM CORRECTION - It was indeed a site error that caused the Choconom to appear as "Limit 1" in the Chocotravaganza Prize Shop. Only Cave monthlies are limit 1. The Choconom was not ever intended to be limit 1 and, in fact, never has during the event so far.
Multiple Choconoms are 100% valid! You're encouraged to collect as many as you want during the event. We apologize for the confusion.