Pre-heat the oven to 350 degrees. Cook pasta in a large pot of boiling water until al dente. Drain and set aside.
In a large skillet, cook and stir ground beef and chopped onion over medium heat until browned. Mix in tomato soup, diced tomatoes, and taco seasoning mix. Stir in pasta.
Spoon the beef mixture into a greased 9×13 inch baking dish. Place into the oven and bake for 30-35 minutes. Within the last 10 minutes of cooking remove from the oven and top with crushed tortilla chips, cheese, green onions, and black olives. Return to the oven and finish cooking. Serve with sour cream.