Some will argue that a little wee piece of dried papaya once every week or two is of no harm to a chin.
Most do not give a chin ANY dried fruit whatsoever and stick to safe treats like apple sticks and dried rosehips.
Either way, 2-3 pieces per day is extremely dangerous. Why? Because stomachs of chinchillas are not developed to process sugar the way that the human digestive system is. Because the can not digest it properly, feeding chins sugary treats (like papaya) can lead to serious and painful consequences for the chin, such as bloat and stasis. These consequences (which can be fatal) are not only extremely painful for the chin but extremely costly for your wallet when you take your chin to the vet.
Whether or not your chin likes the papaya does not determine whether or not it is healthy for them to have it and I think that you should stop giving it to your chin immediately. Your chin might sulk for a day or to, but it doesn't matter. Your chin will get over it. Remember also that chins do not need ANY treats at all, they are just for a human psychological benefit and can sometimes be used as a bonding aid.