In a medium bowl, whisk together mayonnaise, mustard, lemon juice, and salt until well combined.
In a large bowl, toss together chicken, celery, and green onion. Add mayonnaise mixture, stirring until combined. Cover and refrigerate for 30 minutes.
Fold pecans into chicken mixture. Place ½ cup chicken mixture on each pita; garnish with lettuce and tomato, if desired, and fold in half. Serve immediately.
Recipe by Louisiana Cookin' at https://louisianacookin.com/praline-chicken-salad-pitas/