Preheat the oven at 180º degrees. Heat two tablespoons olive oil in a non stick pan. Add minced chicken and saute for five minutes. Add chilli powder and cumin powder. Saute till brown. Add taco sauce and saute well.
Add black beans and sweet corn and salt to taste. Mix well. Grease the baking tray with the remaining olive oil. Layer the base of the tray with tortillas. Pour the chicken mixture on top, and sprinkle some cheese. Repeat for the second layer. Bake for fifteen minutes till cheese is slightly brown.
Remove from oven and garnish with black olives and serve hot.