01 - Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish.
02 - Pat chicken breasts dry and season both sides with salt and pepper. Arrange in the prepared baking dish.
03 - In a medium bowl, combine sour cream, mayonnaise, green onions, onion soup mix, garlic powder, onion powder, and milk. Mix until smooth.
04 - Spread the sour cream and onion mixture evenly over the chicken breasts.
05 - Sprinkle cheddar cheese and, if using, crushed crackers or chips on top.
06 - Bake uncovered for 25-30 minutes, or until the chicken reaches an internal temperature of 165°F and the sauce is bubbly.
07 - Let rest for 5 minutes. Garnish with extra green onions before serving.