Mexican Chicken without pine

1 tablespoon vegetable oil 1 pound chicken breasts cubed, boneless, skinless 1 each onion small, chopped 1 each green bell pepper small, chopped 1 package[...]

1 teaspoon chili powder 2 tablespoons brown sugar 2 tablespoons worcestershire sauce 150 ml chicken broth * 4 each chicken breasts skinless 1 teaspoon celery[...]

1 medium onion thinly sliced 1/2 cup vegetable oil 12 each green olives pitted * 4 cups tomatoes chopped 2 each celery chopped 2 cloves garlic finely chopped[...]