Bring a large pot of salted water to a boil. Cook egg noodles 1 minute less than package directions until just shy of al dente. Drain and set aside.

Heat a large skillet over medium-high heat. Add ground beef and onion; cook 6-8 minutes, breaking up the meat, until beef is browned and onion is soft. Drain excess fat if needed.

Stir in taco seasoning, diced tomatoes with their juices, and tomato sauce. Bring to a simmer and cook 5 minutes until slightly thickened. Remove from heat and stir in sour cream until smooth.

Preheat oven to 350F. In a 9x13 inch baking dish, combine cooked noodles and meat sauce. Fold in 1.5 cups cheese. Spread evenly and top with remaining 0.5 cup cheese and sliced olives.

Bake uncovered 20-25 minutes until cheese is melted and edges are bubbling. Let rest 5 minutes, then sprinkle with cilantro and serve.