How to Make It
In a very large skillet, heat 2 tablespoons of the oil. Season the chicken with salt and pepper and add it to the skillet in a single layer. Cook over high heat, turning once, until browned but not cooked through, 4 to 5 minutes. Using a slotted spoon, transfer to a plate. Pour off the fat in the skillet.
Add the remaining 1 tablespoon of oil to the skillet. Add the onion and bell pepper and cook over high heat, stirring occasionally, until crisp-tender, about 3 minutes. Add the garlic, chile powder and cumin and cook, stirring, until fragrant, 1 minute.
Return the chicken and any accumulated juices to the skillet and cook for 1 minute. Add the tomato sauce, corn and water and cook over moderate heat, scraping up any bits stuck to the skillet, until the chicken is cooked through and the sauce is reduced, about 5 minutes. Transfer to a bowl and serve with corn tortillas, sour cream and cilantro.