If using raw chicken, poach it: place chicken breasts in a pot, cover with water, add a pinch of salt, bring to a boil, then reduce to a simmer and cook 12-15 minutes until cooked through. Let cool, then shred or dice.
In a large bowl, whisk together mayonnaise, sour cream, Dijon mustard, lemon juice, and honey until smooth.
Add the chicken, celery, red onion, toasted nuts, parsley, and dill. Stir gently until everything is evenly coated. If using, stir in smoked paprika.
Season with salt and pepper to taste. Start with 1/2 teaspoon salt and adjust as needed.
Cover the bowl and refrigerate for at least 30 minutes to allow flavors to meld. Serve cold on croissants, bread, lettuce wraps, or with crackers.