Chicken Salad with Apples, Grapes, and Walnuts

cooked chicken breasts, shredded

Granny Smith apples, cut into small chunks

chopped walnuts, or to taste

red onion, chopped

stalks celery, chopped

lemon juice

vanilla yogurt

creamy salad dressing (such as Miracle Whip®)

mayonnaise

seedless red grapes, halved