Preheat oven to 350 degrees. In a medium, non-stick skillet over medium heat, cook chicken until no longer pink. Cut chicken into cubes and return it to the skillet. Add the onion, sour cream, Cheddar cheese, parsley, oregano and ground black pepper. Heat until cheese melts. Stir in stewed tomatoes, water, chili powder, green pepper and garlic. Roll even amounts of the mixture in the tortillas. Arrange in a 9x13 inch baking dish. Cover with taco sauce and 3/4 cup Jack cheese. Bake uncovered in the preheated oven 20 minutes. Cool 10 minutes before serving.