Taco Spaghetti

Taco spaghetti
1 lb. 93% lean ground beef
1 small yellow onion, finely chopped
4 cloves garlic, finely chopped
4 c. water
1 (10-oz. can) diced tomatoes and green chilies
1 (1-oz.) packet or 2 tbsp.taco seasoning
8 oz. spaghetti
4 oz. Velveeta cheese or American cheese, cut or torn into pieces
1 c. (4 oz.) sharp cheddar cheese, shredded
1/2 c. chopped fresh cilantro, plus more for serving
Sour cream or Mexican crema, for serving (optional)