Begin by toasting the pecans. Spread pecans on a dry skillet over medium heat and toast for 5-7 minutes, stirring frequently, until fragrant. Remove from heat and chop coarsely once cooled slightly.

If using whole chicken breasts, poach or bake the chicken until cooked through, then shred finely. Ensure the shredded chicken is relatively dry to avoid a watery salad.

In a small bowl, whisk together the dressing ingredients: mayonnaise, sweet pickle relish, Dijon mustard, lime juice, salt, and pepper until smooth and well combined.

In a large mixing bowl, combine the shredded chicken, drained crushed pineapple, toasted pecans, diced celery, and minced red onion.

Pour the prepared dressing over the chicken mixture. Gently fold all ingredients together until everything is evenly coated. Be careful not to mash the ingredients.

Cover the bowl and refrigerate for at least 1 hour to allow the flavors to meld together. Serve chilled on croissants, lettuce cups, or crackers.