Preheat oven to 350 degrees F.

In a large bowl, combine the ground sirloin, eggs, onion, bread crumbs, green chiles, taco seasoning, salt and pepper until evenly incorporated. Shape into round slightly bigger than a golf ball, placing on a small baking sheet or platter.

Place a large skillet over moderate heat with the oil. Once hot, brown the meatballs in batches, cooking about 2 to 3 minutes per side. You don't need to cook them all the way, they'll continue to cook in the sauce later on! Continue browning the meatballs until all are done, transferring them to a platter or plate as they've finished browning.

Whisk the flour into the skillet, with the remaining fat and all, and cook for about 30 seconds or so. Slowly whisk in the chicken stock and cook until it has thickened. Stir in the enchilada sauce and cook for about 8 to 10 minutes, until slightly thickened as well. Gently stir in the tortillas until evenly coated in sauce. Then nestle the meatballs back into the skillet, coating each with the sauce. Sprinkle with the shredded Monterey jack, and bake until bubbly and the cheese has melted, about 20 to 25 minutes. Carefully remove from the oven and top with cilantro, radish, and cotija cheese right before serving. Enjoy!