Place the chicken on a baking sheet; season with ¼ teaspoon each salt and pepper. Place the prosciutto on a second baking sheet. Roast at 450°F until the chicken is cooked through and the prosciutto is darkened, 6 to 8 minutes.
Steam the broccolini until tender, 3 to 5 minutes. Toss with the oil; season with ¼ teaspoon each salt and pepper.
Top the chicken with the prosciutto. Serve with the broccolini and lemon wedges.
