Preheat the oven to 350°F. Lightly grease a 9x13-inch baking dish with cooking spray.

Pat the chicken breasts dry with paper towels and season them with salt and pepper.

In a deep skillet over medium-high heat, warm 2 tablespoons of olive oil. Brown the chicken for about 5 minutes on each side. Transfer the chicken to the prepared baking dish.

Add butter to the skillet and then mushrooms. Cook for 2 minutes until golden. Transfer the mushrooms to the baking dish with the chicken and layer the bell peppers on top.

In the same skillet, add the remaining olive oil and cook the onions for about 5 minutes until tender.

While the onions are cooking, in a medium bowl, whisk together chicken broth, ketchup, tomato paste, honey, white wine vinegar, Worcestershire sauce, paprika, and chili powder. Set aside.

Sprinkle flour over the onions and cook for another minute. Slowly stir in the chicken broth mixture and cook for 3 to 4 minutes until slightly thickened.

Pour the sauce over the chicken, cover with aluminum foil, and bake for 35 to 45 minutes. Baste the chicken halfway through the cooking time. Remove the foil, baste the chicken with the sauce, and bake for an additional 15 minutes to caramelize the bell peppers.