The answer to this could vary depending on how you define the Columbian Exchange, but I would argue that the Europeans got the better of the deal regardless of how it is defined.
If you only look at the kinds of foods that were involved in the Columbian Exchange, it is hard to state definitively who “won” the exchange. However, I do think that the Europeans won. They got foods that became important staples in Europe rather quickly. These included tomatoes, potatoes, and corn. Chocolate was another important addition to European diets. While we may not think this way today, Europeans of the time would probably have seen tobacco as a gain as well. By contrast, the Native Americans did not gain as much. Grains like wheat did come to the New World, but the most important thing that came over was large animals such as cows and horses. These were important, but arguably not as important as potatoes, tomatoes, and corn.
However, if you include germs in the Columbian Exchange, the Native Americans clearly lost. The germs that came over with the Europeans killed tremendous numbers of Native Americans. The loss of so many lives is an obvious reason to say that the Native Americans got the worst of the Columbian Exchange.