1 pound ground beef
1 (1-ounce) envelope taco seasoning mix
1 (10-ounce) can diced tomatoes with green chilies
1 (15-ounce) can pinto beans, rinsed and drained
6 (1-ounce) bags corn chips
1/4 cup shredded cheddar cheese, optional
1 tablespoon sour cream, optional
1/4 cup fresh cilantro, optional