Preheat oven to 400°. Prepare and bake muffin mix according to package directions. Cool completely and crumble; transfer to a large bowl. Add 1 envelope taco seasoning, eggs, 1-1/2 cups enchilada sauce and meat; mix lightly but thoroughly. Shape meat mixture into 1-1/2-in. balls; bake on greased racks in 15x10x1-in. baking pans lined with foil until lightly browned, 10-12 minutes.
Place meatballs in a 5- or 6-qt. slow cooker. Combine remaining enchilada sauce, salsa, chiles, 1/2 cup cheese and remaining envelope taco seasoning; pour over meatballs. Sprinkle with remaining cheese. Cook, covered, on low until meatballs are cooked through, about 3 hours.
Test Kitchen tips
Serve enchilada meatballs with tortilla chip scoops to capture all the rich flavor. The chips and meatballs together taste like mini tacos.
Set these out on the buffet with traditional taco toppings, including shredded lettuce, diced tomato and cheddar cheese.