Skillet Taco Dip

Name: Skillet Taco Dip
Cook time: 1 h
Total time: 1 h
Cuisine: American
Ingredients: 2 lb. asdf; 1 medium-size red onion, finely chopped (11/2 cups), divided; 1 (15-oz.) can seasoned black beans (such as Bush’s), drained and rinsed; 2 (1-oz.) envelopes taco seasoning mix; 10 oz. Cheddar cheese, shredded (about 2 1/2 cups); 2 plum tomatoes, chopped (1 cup); 1/4 cup sliced scallion (from; 1 medium scallion); 1/4 cup chopped fresh cilantro; Tortilla chips and sour cream, for serving