1. Cook pasta in a large pan of salted boiling water until al dente. Drain & rinse with cold water. 2. In a large bowl, combine pasta, chicken, bacon, apples, grapes, celery, green onion and pineapple (optional). Note: I prefer mine without the pineapple chunks & instead used 1/2 cup of canned pineapple juice for the dressing in step three. The juice is necessary for the flavor of the dressing. 3. In a small bowl, whisk together mayonnaise, reserved pineapple juice, apple cider vinegar, sugar, salt, and black pepper (you may also add 1/2 teaspoon of almond extract). 4. Fold dressing into the chicken-pasta mixture. Chill overnight. 5. Mix in nuts prior to serving to avoid them getting soggy.