In a large skillet, brown the ground beef over medium-high heat. Drain off any excess grease.
Stir in the taco seasoning, diced tomatoes, Rotel, and water. Bring to a simmer.
Add the uncooked spaghetti to the skillet, breaking it in half if necessary to fit. Cover and reduce heat to medium-low. Cook for 15-20 minutes, or until the pasta is tender and most of the liquid has been absorbed, stirring occasionally to prevent sticking.
Stir in the shredded cheddar cheese and sour cream until well combined and the cheese is melted.
This recipe is easily adaptable. You can substitute ground turkey or chicken for the ground beef, or add a can of drained black beans for extra protein and fiber.