1. Bring a large pot of salted water to a boil and cook the spaghetti until al dente. Reserve 1 cup of pasta water, then drain the spaghetti.

2. Heat olive oil in a large deep skillet over medium-high heat. Add the ground beef and cook until browned, breaking it into small crumbles. Drain excess grease if needed.

3. Add the diced onion and green bell pepper. Cook for 4 to 5 minutes, until softened.

4. Stir in the garlic and cook for 30 seconds, just until fragrant.

5. Sprinkle in the taco seasoning and stir until the beef and vegetables are evenly coated.

6. Add the diced tomatoes with green chiles, tomato sauce, and beef broth. Stir and simmer for 5 to 7 minutes.

7. Reduce the heat to low and stir in the cream cheese until fully melted and smooth.

8. Add the cooked spaghetti and toss until the pasta is coated in the creamy taco sauce.

9. Stir in the cheddar cheese and Monterey Jack cheese until melted. Add a splash of reserved pasta water if the sauce needs loosening.

10. Season with salt and black pepper, then garnish with fresh cilantro and serve with sour cream, jalapeños, or crushed tortilla chips if desired.