Joan Lunden's Chicken Tortilla Soup

Ingredients

• 1 chopped medium onion (about 1 cup)
• 2 minced garlic cloves (about 2 tsps)
• 2 tbsps vegetable oil
• one 4 ounce can green chiles -- chopped
• a 15-ounce can italian-style stewed tomatoes (chopped and with their own juice)
• 4 cups chicken broth
• 1 tsp lemon pepper
• 2 tsps worcestershire sauce
• 1 tsp chili powder
• 1 tsp ground cumin
• 1/2 tsp hot sauce
• 4 tbsp flour
• 1/2 cup water
• 1 pound skinless boneless chicken breasts, cut into small cubes
• 1/3 cup non-fat sour cream