Preheat oven to 375 degrees F. In a large skillet, thoroughly brown chicken strips in vegetable oil; drain fat. Add garlic and onion; saut, until tender. Add sauce, olives, chilies, corn, chili powder and oregano. Simmer, covered, 15 minutes, stirring occasionally. Spoon mixture into a 13 x 9-inch baking dish. Evenly top casserole with crushed tortilla chips and cheese. Bake, uncovered, 10 minutes or until bubbly.