Preheat oven to 350 degrees F (175 degrees C). Bring a large pot of lightly salted water to a boil. Cook elbow macaroni in the boiling water, stirring occasionally until tender yet firm to the bite, 8 minutes. Drain. Transfer cooked macaroni to a 9x13-inch casserole dish. Add 2 cups shredded Cheddar cheese, Alfredo sauce, and mustard; mix thoroughly until macaroni is evenly coated. Mix in remaining 2 cups cheese and drained tomatoes and green chiles. Top with bread crumbs. Bake until bubbly and cheese is melted, about 30 minutes.