Preheat an oven to 350°F.
Season the chicken generously with salt and pepper. In a large ovenproof fry pan over medium-high heat, warm the olive oil. Add the chicken and cook, turning once or twice, until golden brown on both sides, about 6 minutes total. Transfer the chicken to a plate.
Add the onion, roasted bell peppers and garlic to the drippings in the pan, reduce the heat to medium and sauté until the vegetables are softened, 4 to 5 minutes.
Stir the rice into the vegetables, stirring to coat the rice well. Add the chicken broth, oregano, and put the chicken back in the pan. Transfer the entire pan to the oven and cook for 45 minutes.
Uncover the pan and stir in the tomatoes with their juices. Cover and continue to bake until the rice is tender and most of the liquid is absorbed, about 15 minutes more. Season with salt and pepper. Serve directly from the pan. Serves 4 to 6.