I imagine that you have tried to sell it to a dealer. Bikes are not cheap in Chile, so I'm sure someone will be willing to get it (maybe not, I ignore if the customs would be a pain; where is it registered?). Or try to park it (for sale) in a dealer till some foreigner arrives and you/they sell it to him. You could keep offering it on line.
If you want help with the language to write an add in a Chilian site, just let me know, I'm Spanish and would be have to give a hand. Or if you want to draft/sign some kind of contract with the dealer/private.
In any case, keep the nice side/memories of the trip.
Safe trip back,