1 firm-ripe mango (3/4 pound), peeled, pitted, and chopped
1 cup red seedless grapes (5 ounces), halved
1/2 cup salted roasted cashews, coarsely chopped
Bring 4 cups water to a simmer with chicken broth in a 2- to 3-quart saucepan. Add chicken and simmer, uncovered, 6 minutes. Remove pan from heat and cover, then let stand until chicken is cooked through, about 15 minutes. Transfer chicken to a plate and cool 10 minutes. Chop into 1/2-inch pieces.
While chicken is cooling, whisk together mayonnaise, yogurt, curry, lime juice, honey, ginger, salt, and pepper in a large bowl. Add chicken, onion, mango, grapes, and cashews and stir gently to combine.