Creamy Chicken Sopas

Name: Creamy Chicken Sopas
Ingredients: 2 quarts low-sodium chicken broth; 2 boneless, skinless chicken breasts (6 to 8 ounces each); Kosher salt and freshly ground black pepper; 3 tablespoons vegetable oil; 2 medium carrots, cut into small dice; 2 celery stalks, cut into small dice; 1 medium yellow onion, cut into small dice; 3 ounces ham steak or boiled ham slab, cut into small dice (about 1/2 cup); 3 cloves garlic, minced; 3 tablespoons fish sauce; 2 cups macaroni; One 10 1/2-ounce can condensed cream of chicken soup or one 12-ounce can evaporated milk; Chopped scallions, for garnish