Cut tortillas into strips. Heat oil in skillet. Fry strips over medium heat til crisp. Drain on paper towel, set aside.
Put the chopped onions, sliced zucchini and carrots and chopped tomatoes and bell peppers and the chicken broth, tomato sauce and salt and pepper in a pot. Bring to boil. Reduce heat and cover. Simmer 15 minutes. Pour soup into serving bowls. Lay tortilla strips on top of each serving and sprinkle on cheese. Serve hot. Serves 4