Step 1

Stir 1/2 cup panko breadcrumbs, 1/4 cup finely chopped scallions, 1 large egg, 1 1/4 teaspoons of the chili powder, 1 1/4 teaspoons kosher salt, 1/2 teaspoon of the ground cumin, and 1/4 teaspoon black pepper together in a large bowl.

Step 2

Add 1 1/2 pounds ground beef and mix until evenly combined; do not overmix or the meatballs will be tough. Scoop out the mixture in heaping 2-tablespoon portions (22 to and roll between damp hands until a smooth ball forms.

Step 3

Heat 1 tablespoon olive oil in an oven-safe 12-inch frying pan or skillet over medium-high heat until shimmering. Add the meatballs in a single layer and cook until browned on the bottom, about 1 1/2 to 2 minutes. Flip the meatballs and cook until browned on the other side, 1 1/2 to 2 minutes more. Transfer to a large plate (the meatballs will not be fully cooked). Remove all but 1 tablespoon of fat from the skillet.

Step 4

Reduce the heat to medium. Stir in 1 (about 24-ounce) jar marinara sauce, 1 (7-ounce) can diced green chiles and their juices, the remaining 1 1/4 teaspoons chili powder, and the remaining 1/2 teaspoon ground cumin. Bring to a simmer.

Step 5

Transfer the meatballs into the sauce. Cover and simmer, flipping the meatballs halfway through, until they’re cooked through and an instant-read thermometer inserted into the center of a meatball registers at least 165°F, 10 to 12 minutes total. Meanwhile, arrange a rack 6 inches from the broiler and heat to broil.

Step 6

Sprinkle 1/2 cup shredded sharp cheddar cheese and 1/2 cup shredded Monterey Jack cheese evenly over the meatballs. Transfer the skillet to the oven and broil uncovered until the cheese is melted and bubbly, 2 to 3 minutes. Garnish with thinly sliced scallions.