Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish with olive oil or non-stick spray.

Bring a large pot of salted water to a boil and cook the spaghetti according to package instructions until al dente, about 8-10 minutes. Drain and set aside.

In a skillet over medium heat, warm a tablespoon of olive oil and add the minced garlic. Sauté for about 1 minute until fragrant.

Add the shredded chicken, diced tomatoes, smoked paprika, salt, and black pepper to the skillet. Cook for 2-3 minutes.

In a large bowl, combine the spaghetti with the chicken mixture, sour cream, milk, half of the Monterey Jack cheese, and half of the cheddar cheese. Mix well.

Transfer the mixture into the greased baking dish and top with the remaining cheeses and sliced green onions.

Bake in the preheated oven for 20 minutes or until the cheese is melted and bubbly.

Let cool for a few minutes before serving hot, garnished with any leftover green onions.