Preheat the oven to 450 degrees F (230 degrees C). Spray a 9x12-inch brownie pan with cooking spray.
2
Heat olive oil in a large skillet over medium heat. Add onion and cook until soft, about 5 minutes. Stir in chicken, bacon, and roasted garlic. Season with salt, pepper, and garlic powder. Stir in green onions.
3
Mix ranch dressing and sour cream together in a small bowl. Remove chicken mixture from heat and stir just enough ranch mixture into the skillet to barely coat chicken.