Cheesy Southwestern Chicken Casserole

Name: Cheesy Southwestern Chicken Casserole
Ingredients: Cooking spray; 3 cups shredded, cooked chicken; 1 medium white onion; 1 (14.5-ounce) can black beans; 1 (14.5-ounce) can corn kernels; 1 (15-ounce) can diced tomatoes; 1 (4-ounce) can diced green chiles; 1 teaspoon chili powder; 1 teaspoon paprika; 1 teaspoon garlic powder; 1 teaspoon ground cumin; 1 1/2 teaspoons kosher salt; 1 cup unsalted chicken broth; 1/4 cup thinly sliced scallions; 2 tablespoons coarsely chopped fresh cilantro; 2 cups shredded Mexican blend cheese