Preheat oven to 400°F (200°C). If chicken is not cooked, bake chicken breasts for 25 minutes, then shred with forks.
In a large 9 x 13 inch baking dish, combine diced onion, bell pepper, jalapeño, rice, chili powder, garlic powder, cumin, oregano, and salt.
In a separate bowl, whisk together chicken broth, tomato paste, and olive oil until smooth.
Pour the broth mixture into the baking dish and stir well to combine with the rice and spices.
Add shredded chicken, black beans, and corn to the baking dish and mix gently to incorporate.
Cover the dish with aluminum foil and bake for 50 to 60 minutes, until the liquid is absorbed and rice is tender.
Remove foil and sprinkle grated cheese evenly over the casserole.
Return to oven and bake uncovered for an additional 5 to 10 minutes until cheese melts and turns golden.
Remove from oven, let cool slightly, and garnish with fresh cilantro and green onion before serving.