Prepare the Cheese
Shred the cheddar cheese using a box grater if using a block cheese. Set aside for later use. Freshly shredded cheese melts more smoothly than pre-packaged shredded cheese, which often contains anti-caking agents.
Brown the Meat
In a large skillet or pot, cook the ground beef over medium-high heat until completely browned and no pink remains, about 5-7 minutes. Break up the meat with a wooden spoon as it cooks for even browning. Once cooked, remove from heat and drain away excess grease to prevent a greasy final dish.
Add Seasonings
Return the pot to heat and add the taco seasoning and diced tomatoes with green chiles. Stir until the meat is thoroughly coated with the seasoning mixture. The tomatoes will add moisture and flavor to the dish.
Add Pasta and Liquid
Add the spaghetti noodles to the pot and pour water or beef broth over them. Use a spoon to gently press the noodles down into the liquid mixture to ensure they're fully submerged and cook evenly. Breaking the noodles in half before adding them can make them easier to submerge.
Cook the Pasta
Bring the mixture to a boil, then cover with a lid and reduce heat to low-medium. Simmer for 7-12 minutes, or until the liquid has reduced and pasta is cooked to al dente. Stir halfway through cooking to prevent sticking and ensure even cooking. The cooking time may vary depending on the thickness of your pasta.
Add Cheese
Lower heat to the lowest setting and add cream cheese and shredded cheddar cheese, stirring until evenly combined and melted. If desired, reserve some shredded cheese for garnishing on top. The cream cheese adds a wonderful creaminess while the cheddar provides that classic taco flavor.
Serve
Remove from heat and serve immediately with additional toppings if desired. The pasta will continue to absorb sauce as it sits, so serving promptly ensures the best texture and consistency.