Reserve half the tomatoes and cilantro and set aside.
Place all ingredients except sour cream and cheese in large pot. Cover and bring to a boil. Once boiling uncover and continue to cook until most of moisture in gone and spaghetti is cooked. Stir in the sour cream and cheese. Cook until cheese melts.
Stir in the reserved tomatoes and cilantro. Top with more sour cream for serving (optional)