Melt the butter in a pan over medium-low heat and add the onions, salt, and garlic powder. Stir frequently until onions are soft and translucent, about 20 minutes. Add the beer and bring to a boil. Reduce the heat to a simmer and stir occasionally until the beer has evaporated, about 30 minutes. Remove onions from the pan and allow to cool.
Mix together the cream cheese, sour cream, Worcestershire sauce, and horseradish. Once the onions are cooled, add them to the mixture and stir. Refrigerate for at least one hour before serving. Garnish with fresh chives and serve with your favorite Utz Potato Chips.