Preheat oven to 350°F.
Spray a glass baking dish evenly with cooking spray. Place onions in baking dish; top with chicken filets. Season the chicken evenly with salt, black pepper and garlic powder. Pour chicken broth into baking dish and bake for 20 minutes.
Remove baking dish from oven. Transfer chicken breast filets to container and reserve. To baking dish, add rice, bell peppers, peas, cilantro and oregano. If desired, add 2 shakes of yellow coloring. Stir rice mixture. Arrange reserved chicken breast filets over rice. Cover and bake for 25 minutes.
Remove from oven, gently stir rice mixture, cover with foil and bake an additional 10 minutes or until chicken is fully cooked and rice is tender and all liquid is absorbed.