In a large skillet cook the ground beef with the green chiles, onions, garlic, bell pepper, dried chili flakes (if using) and chili powder; cook over medium heat until beef is no longer pink; drain fat completely (you can prepare this mixture up to a day in advance and refrigerate).
Season with seasoned salt and black pepper to taste then transfer to a large bowl.
Stir in the tortilla pieces with cream of mushroom soup, black olives, enchilada sauce, sour cream and 1-1/2 cups shredded cheese; mix to combine.
Transfer to prepared baking dish.
Cover and bake for about 30 minutes.
Uncover and sprinkle with about 2 cups (or more of shredded cheese then chopped tomatoes.
Return to oven and bake uncovered until casserole is bubbly and the cheese has melted (about 8-10 minutes).