Preheat oven to 350 degrees.
Cook meatballs in enchilada sauce according to package instructions.
Fill sandwich rolls with meatballs (approx. 3 meatballs per roll).
Place filled sandwich rolls in a 9x13 inch baking pan.
Top with additional sauce from pan and sprinkle with cheddar cheese.
Cover with foil; bake at 350 degrees for 15 minutes or until cheese is melted.
Remove from oven; top with diced tomato, cilantro, and sour cream mixture.