Smoky Meatball Subs

Name: Smoky Meatball Subs
Ingredients: 1 pound meatloaf mix (ground beef, pork and veal); 1/4 cup finely crushed tortilla chips; 1 large egg, beaten; 1/4 cup chopped fresh cilantro, plus 3 sprigs; 1/4 cup finely chopped scallions, plus more for garnish (optional); 3 cloves garlic; 1 minced, 2 smashed; 3 teaspoons ancho chili powder; 2 teaspoons ground cumin; Kosher salt; 1 tablespoon extra-virgin olive oil; 2 cups canned fire-roasted diced tomatoes; 4 crusty sub rolls, halved and split open; Diced avocado and crumbled Mexican cheese, for garnish (optional)