Season the chicken with salt and pepper. In a medium cast iron skillet or other wide, flat skillet, heat the olive oil over medium high heat and brown the chicken. Remove from the pan, add the onion, and cook over medium heat until caramelized.
Add the chorizo and crisp it up. Add the tomato and cook for a minute. Then add the rice and toast it for a couple minutes. Add the butter beans,broth, and browned chicken, and season to taste. Shake the pan so all the ingredients are distributed evenly. Bring the mixture to a boil.
Once boiling, lower the heat to the lowest setting and cover the pan tightly with a lid or with foil. Cook, covered, for about 25 minutes (you can check it towards the end to see if you need to add more water or cook it longer). In the last five minutes of cooking, sprinkle the peas over the top, cover, and cook until the rice is tender.