1. Place the apples in a bowl with the lemon juice.
2. Set aside.
3. Meanwhile, mix together the celery, shallots, pineapple pieces, garlic, and walnuts.
4. Add to the apple mixture.
5. Stir in the remaining ingredients, mayonnaise, sugar, and pepper.
6. Add cooked chicken and mix well.
7. Pour onto serving platter lined with lettuce, if desired.
8. Garnish with chopped walnuts.