Wash and cut up lettuce. Chop tomatoes and add to lettuce. Drain beans and olives and add. Grate cheese and add. At this point the salad bowl can be covered and put in the refrigerator until just before serving. When you are ready to serve the salad, add dressing and toss. At last moment add the crushed tortilla chips and toss again. Serve immediately. Serves 4-6 persons.