For easy prep, buy a pre-cooked rotisserie chicken from the grocery store.
This recipe is best made using a food processor. If you do not have one, you can finely chop the ingredients and blend them.
Place the pecans, onion, and celery in a food processor and pulse a few times to roughly break them down. Add the chopped chicken and pulse again to roughly break down the chicken. Add the mayonnaise, parsley, lemon juice, mustard, and salt and pepper to taste. Blend the ingredients until mixed but slightly chunky.