Preheat your oven to 375°F and lightly spray a 9x13 inch baking dish with nonstick cooking spray. Position your oven rack in the center for even heat distribution.

In a medium bowl, combine the sour cream, garlic powder, seasoned salt, black pepper, and 1 cup of the Parmesan cheese. Mix thoroughly until smooth and well blended.

Arrange the chicken breasts in a single layer in the prepared baking dish, making sure they don't overlap. If chicken breasts are larger than 8 ounces each, consider pounding them to uniform thickness (about 1 inch) for even cooking.

Spread the sour cream mixture evenly over each chicken breast, covering them completely from edge to edge.

Sprinkle the remaining 1/2 cup of Parmesan cheese over the top of the coated chicken breasts.

Bake for 25-30 minutes until the chicken reaches an internal temperature of 165°F in the thickest part. The coating should look set and juices should run clear.

Move your oven rack to about 6 inches from the broiler element and switch oven to broil. Broil for 2-3 minutes, watching constantly, until the top turns lightly golden brown. Remove promptly to prevent burning and let rest for 3-4 minutes before serving.