#1 Preheat the oven to 425°F. #2 Preheat a large skillet over medium-high heat. Add 2 tablespoons extra-virgin olive oil and onion, sautéing until translucent. Stir in ground beef and cook, breaking it apart often, until it begins to brown. Drain excess fat from the skillet, then season the ground beef with chili powder and cumin. Add diced tomatoes, black beans, and corn, heating the mixture through for about 3 minutes. Season with salt and pepper to taste. #3 Coat a shallow baking dish with remaining oil. Layer meat and beans, top with tortillas and cheese. Repeat layers twice. Bake for 12-15 minutes or until cheese is brown and bubbly. Top with the chives and serve with your favorite toppings.