In a large bowl, whisk together baby food, yogurt, milk, salt, and pepper. Then stir in chicken, grapes, celery, and green onions until everything is evenly coated.
Cover and chill in refrigerator for 2 hours. Before serving, gently fold in mandarin oranges, careful not to break them up too much.
Serve over a bed of lettuce, on bread or rolls, or with crackers. Enjoy!