Combine buttermilk, egg, biscuit mix and sugar.
Beat one minute to blend thoroughly.
Gently stir in Swiss cheese, olives and walnuts; spoon into well-buttered loaf pan (9" x 5" x 3" or comparable size).
Bake in moderate oven, 350 degrees, for 50 to 55 minutes (a crack along the top of the loaf usually occurs); cool 5 minutes before removing from pan.
Unused portions will keep well when wrapped and stored in refrigerator or freezer.