In a large saucepan, over medium-high heat, add butter and oil. Add chopped onions when butter melts. Stir onions often until they turn a golden brown and start to caramelize. This can take anywhere from 10-20 minutes depending on the size of your pan. Add in water 1 tablespoon at a time when the onions are cooking. The water will absorb from the heat.
In the meantime, combine the sour cream, mayo, Worcestershire sauce, garlic powder, salt, pepper and 1 tablespoon of chives in a medium sized bowl.
Once the onions are done, add them to a food processor and pulse for a few seconds. You don't want to puree it. You do want the onions to be slightly chunky still. Add the onions to the dip to the mixture and stir until combined. Place the dip in the refrigerator for an hour before serving and top with leftover chives. Stir one more time when chilled and sprinkle more chives on top. Dip with your favorite chips!