01 - Melt butter in a large skillet over medium heat. Add chopped onions, salt, pepper, and sugar. Cook stirring frequently until onions turn golden brown and caramelized, approximately 18–20 minutes. Remove from heat and allow to cool completely to room temperature.
02 - In a medium mixing bowl, combine mayonnaise, sour cream, softened cream cheese, Worcestershire sauce, and fresh chives. Whisk together until mixture achieves smooth and creamy consistency throughout.
03 - Add cooled caramelized onions to the creamy base. Fold together thoroughly until onions are evenly distributed. Taste mixture and adjust seasoning with additional salt or pepper if desired.
04 - Cover bowl tightly with plastic wrap or lid. Refrigerate for minimum 1 hour to allow flavors to meld together. Dip can be prepared up to 2 days in advance and stored refrigerated.
05 - Transfer chilled onion dip to serving bowl. Sprinkle additional fresh chives over top as garnish. Arrange potato chips alongside dip for serving.