Preheat oven to 350 degrees. Spray a 3-quart baking dish with nonstick cooking spray. Set aside.
Heat olive oil in latrge skillet over medium-high heat. Add onion and cook until translucent, about 5-6 minutes, stirring often. Add garlic and cook for one more minute. Add tomatoes, corn, green chiles, picante sauce, cumin, chili powder and oregano. Bring to a boil, then reduce heat and simmer, uncovered for 8-10 minutes. Stir in the beans and the chicken.
Spread one-third of the chicken mixture over the bottom of the prepared dish. Top, overlapping with five tortillas that have been cut into quarters and 1 cup of the shredded cheese. Add another one-third of the chicken mixture. Top with remaining 5 tortillas, chicken mixture and remaining 1 cup cheese.
Bake, covered for 25-30 minutes until heated through. Remove from oven and let stand for 10 minutes before serving. Garnish with chopped cilantro, is desired.