In cup, stir together cornstarch, 1/2 cup chicken broth, and lemon juice until smooth; set aside. In 10-inch skillet over high heat, heat remaining broth to boiling. Add carrots and onion; cook until carrots are tender-crisp, stirring occasionally. Add snow peas; cook 2 minutes. Reduce heat to medium. Stir cornstarch mixture into skillet. Cook until mixture boils and thickens, stirring constantly. Serves 5.