Preheat grill or grill pan to medium-high. Toss chicken with 2 tsp. olive oil, 2 tsp. chili powder, and black pepper. Drizzle mango and stone fruit with 2 tsp. olive oil.
Grill cutlets for 5 to 7 minutes, turning once until cooked through. Transfer to plate; cover to keep warm.
Grill mango and stone fruit cut side down until lightly charred for 1 to 2 minutes, turning once.
Warm tortillas on grill for about 1 minute on each side. Wrap in foil to keep warm.
Cut stone fruit into bite-size pieces. Cut crosshatch in mango flesh, invert peel, and cut fruit away from peel.
In a bowl, whisk together lime juice, 1 tsp. chili powder, 2 Tbs. olive oil, and a dash of salt and pepper. Add black beans, chopped fruit and scallions.