Heat oven to 190ºC . Grease a 2 litre casserole. Put chicken and celery into casserole. Blender chop nuts and add to chicken. Put 2 cups of potato chips into blender container, cover and process 4 cycles at (stir). Empty onto wax paper and set aside. Repeat with remaining chips. Put remaining ingredients into container, cover and process at (blend) until smooth. Add to chicken and mix well. Sprinkle potato chip crumbs over top and bake for 30 minutes. A cycle is defined as a 1 second pulse operation with a pause for food to settle before repeating.