Heat olive oil in a large pot or Dutch oven over medium-high heat. Add the diced onion and cook for 3-4 minutes until softened.
Add the ground beef and cook, breaking it up with a spoon, until browned and no pink remains, about 5-7 minutes. Drain excess fat if needed.
Stir in the taco seasoning and cook for 1 minute until fragrant.
Add the uncooked pasta, beef broth, diced tomatoes with green chiles (with their juices), and canned green chiles. Stir well and bring to a boil.
Reduce heat to medium-low, cover, and simmer for 12-15 minutes, stirring occasionally, until pasta is tender and most of the liquid is absorbed.
Remove from heat and stir in the sour cream and 1½ cups of shredded cheese. Mix until cheese is melted and everything is creamy.
Top with remaining cheese and your favorite taco toppings. Serve immediately and watch it disappear!