1. Coat a 2-quart round casserole with nonstick spray; set aside. Coat an unheated large nonstick skillet with nonstick spray. Heat skillet over medium-high heat. Add corn; cook about 5 minutes or until corn begins to lightly brown. Add potatoes; cook and stir 5 to 8 minutes longer or until potatoes begin to brown. Stir in tomatoes, chipotle peppers, 1/2 teaspoon chili powder, 1/2 teaspoon cumin, and the oregano. Remove from heat; transfer mixture to the prepared casserole.
2. Wipe skillet clean. Add oil to skillet and heat over medium-high heat. Sprinkle chicken evenly with 1/4 teaspoon salt, 1/4 teaspoon chili powder, and 1/4 teaspoon cumin. Brown chicken in hot oil, turning once to brown both sides (about 3 minutes on each side). Place chicken on top of potato mixture in casserole.
3. Bake, uncovered, in a 375 degree F oven for 20 minutes or until bubbly and chicken is no longer pink. Sprinkle with cheese. Makes 4 servings.