Heat a large skillet over medium-high heat. Add the ground beef and cook for about 5-7 minutes, breaking it up with a spatula until it’s nicely browned and no longer pink. Drain excess fat.

Stir in the taco seasoning and water into the browned beef, ensuring everything is coated evenly. Bring to a gentle simmer; cook for about 5 minutes until the sauce thickens.

While the beef simmers, bring a large pot of salted water to a boil. Add the elbow macaroni and cook according to package instructions, typically about 8-10 minutes, until al dente. Drain the macaroni.

In the same pot, heat a splash of olive oil. Add the diced tomatoes and sauté for 2-3 minutes until they soften and release juices.

Add the beef mixture and cooked macaroni back into the pot with sautéed tomatoes. Stir together until well combined, ensuring the macaroni is evenly coated.

Pour in the milk and stir, then add the shredded cheddar and mozzarella cheese. Mix over medium heat until the cheese has melted completely.

Remove the pot from heat and fold in the sour cream until fully incorporated. Taste and adjust seasonings if desired.

Spoon portions into bowls and garnish with freshly chopped green onions. Serve hot and enjoy!