Heat oven to 375°F. Coat large nonstick skillet with nonstick cooking spray.
If using chicken, heat 1 teaspoon oil in coated skillet over medium-high heat. Add chicken; sauté until lightly browned, 3 to 4 minutes. Remove chicken; reserve. If using beans instead of chicken, reserve the beans to add in Step 4.
Heat the 1 teaspoon oil in skillet (if using beans). Lower heat to medium; add mushrooms, onion, green pepper and jalapeno to skillet; sauté until tender, about 4 to 5 minutes.
Into skillet, stir tomato sauce, boiling water, rice, corn, chicken or beans, chili powder, salt and garlic powder into skillet. Scrape into shallow 2-quart casserole, spreading evenly; cover with aluminum foil.
Bake in 375°F oven 45 minutes or until heated through, stirring once. Uncover casserole; sprinkle top with mozzarella cheese. Bake for 5 minutes more to melt cheese.
262 calories, 4 g fat (1 g saturated), 20 g protein, 38 g carbohydrate. 737 mg sodium, 35 mg cholesterol.
249 calories, 3 g fat (1 g saturated), 12 g protein, 48 g carbohydrate, 765 mg sodium, 3 mg cholesterol.
