Frankfurt to Buenos Aires to Santiago de Chile, can I buy Nutella in Frankfurt Duty free and not haven taken away in Buenos Aires?

I just checked the Argentinian Airport Security Police website (Policia de Seguridad Aeroportuaria). They have a Traveler Information Section (información al viajero) and it says you are forbidden to bring "home-made food, vegetables, sausages, milk and its derivatives". It also states that for a complete list you should consult the National Service for Health and Agricultural Quality (Senasa). I checked that website too and there is a complete list of food products you can (or cannot) bring to Argentina. After reading, it seems to me that you can bring industrialized food, for your own personal consumption as long as the food products are properly labeled and in quantity just for personal consumption.

Once in Ezeiza (main Buenos Aires Airport), I've seen a policewoman confiscate a bottle of water from a traveler, but the bottle was opened. I think you won't have a problem bringing your Nutella and liquor, but I suggest you bring them in it's original packing, preferably sealed.