Bring a large pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente. Drain and set aside.
In a large skillet over medium heat, add the ground beef or turkey. Cook until browned, breaking it apart with a wooden spoon, about 5-7 minutes.
Add the diced onion and minced garlic to the skillet. Sauté for another 3-5 minutes until the onion is translucent.
Stir in the taco seasoning, diced tomatoes (with juices), and broth. Bring to a simmer and cook for about 5 minutes, allowing the flavors to meld.
Lower the heat and stir in the cooked pasta, sour cream, and half of the shredded cheese. Mix until everything is well combined and the cheese is melted.
Taste and season with salt and pepper as needed.
Serve the pasta in bowls, topped with the remaining cheese and chopped cilantro if desired.