On a large serving plater or salad plate, assemble the salad. Place the lettuce on the bottom of the plate, then black beans on top of the lettuce. Spoon salsa over the black beans, then spoon the guacamole over the salsa. Next place the black olives on top of the guacamole. The top layer is cheddar cheese. Arrange the tortilla chips around the edges of the platter. Serve with sour cream if needed.