In a large pot, heat a splash of oil over medium heat. Add ground beef, onion, and garlic. Cook for 5–6 minutes until beef is browned and onions are translucent.

Pour in water and add diced tomatoes along with taco seasoning. Bring to a boil, stirring to dissolve seasoning.

Break spaghetti into thirds and add to the mixture. Reduce heat to medium-low and cover. Let simmer for 10-12 minutes, stirring occasionally.

Once spaghetti is tender, remove from heat and add Velveeta and cheddar cheese. Stir until cheeses melt into the sauce.

Dish out the Taco Spaghetti and top with cilantro and sour cream.