Melt together olive oil and butter just under medium heat. Add diced onions and cook for 20-25 minutes until deeply caramelized. Add brown sugar after 15 minutes. Stir often. Remove from the heat.
To a mixing bowl add cream cheese, mayonnaise, sour cream, sriracha, salt, pepper, onion powder and the cooked onions. If your cream cheese hasn't softened to room temperature you can add everything to the pan of onions so the residual heat can help soften the cream cheese so it incorporates.
Add the dip to a serving bowl and chill in the refrigerator for at least 2 hours.
Top with fresh or dried chopped chives and serve with potato chips.