Add cubed cooked chicken to a medium glass mixing bowl.
Toss in halved grapes, diced Gala apple, and diced red onion.
In a small bowl, combine mayonnaise, honey mustard, garlic powder, and black pepper.
Mix the dressing until smooth.
Pour the dressing over the salad mixture.
Gently toss everything together until evenly coated.
Taste and adjust seasoning if needed.
Chill before serving, or enjoy immediately!