Set a small, dry skillet over medium-low heat. Add the pine nuts and cook 2-3 minutes, stirring frequently, until toasted. Remove from heat.
Add the chicken, celery, thyme, parsley, and toasted pine nuts to a mixing bowl. Mix to combine.
In a small bowl, whisk together the lemon juice, mustard, shallot, and olive oil. Season to taste with salt and pepper.
Pour the dressing over the chicken; mix to combine. Eat immediately or refrigerate until chilled.
Serve the chicken salad on croissants, with pita bread, or in lettuce cups.