Place tortillas on baking sheet. Bake about 10 minutes or until crisp. Cool; break into small pieces. Set aside.
Stir together chicken, All-Bran cereal, cheese, enchilada sauce, and tomato sauce. Pour into 1 1/2-quart flat casserole dish. Bake for 30 minutes or until thoroughly heated. Remove from oven.
Place 1/2 cup chicken mixture on plate. Layer yogurt, lettuce, green onion, and tomato on top of chicken mixture. Sprinkle with tortilla pieces and serve right away.