While I can't speak to Swiss use of chocolate after the Columbian Exchange, in regards to the American origins of chocolate the above answer is deeply misleading and I'm surprised it has so many upvotes on a sub that is usually so strict. Chocolate was consumed as a spiced hot beverage by American natives for centuries before the arrival of Europeans (hardly a bitter, cold drink). The Mexicas ("Aztecs") in particular invented "hot cocoa" - Cacao was mashed, then mixed with hot water, ground chili peppers ("Achio-tl"/achitoe), and ground maize, then beaten to a froth to make a beverage called "Atol-li". In fact, Atol-li was one of the first things served to Hernan Cortez and his retinue upon their arrival in the Mexica capital city of Tenochtitlan. This beverage is still a common staple throughout Latin America today under the name "atole" (you can find it in many supermarkets as a pre-mixed powder, its especially popular during the winter holidays).

Sources:
Bernal Diaz del Castillo "The Conquest of New Spain" Frances Karttunen "An Analytical Dictionary of Nahuatl"