In a 2-1/2-quart glass salad bowl layer black beans, lettuce, tomato, cheese, olives, and onion.
For dressing, in a medium bowl stir together avocado dip, sour cream, chili peppers, milk, garlic, and chili powder. Spread over the top of the salad. If desired, sprinkle with chopped tomato. Cover the surface with plastic wrap and chill for at least 2 hours or up to 24 hours.
Before serving, toss salad together and serve over crushed tortilla chips. Makes 4 servings.