Chicken Tamale Pie

Name: Chicken Tamale Pie
Ingredients: 3 cups diced cooked chicken (about 12 ounces); 1 1/2 cups prepared salsa; One 15-ounce can black beans, drained and rinsed; 1 1/2 cups chicken broth; 1 tablespoon chili powder; 2 scallions (white and green parts), sliced; 3/4 cup cornmeal; 1 cup shredded sharp Cheddar cheese; 1 tablespoon unsalted butter; Kosher salt and freshly ground black pepper; Sour cream, for serving