Cook the chicken and onion in a large skillet. Heat the oil over medium heat. Add the cubed chicken and chopped onion. Cook, stirring occasionally, until the chicken is mostly cooked through.

Season the mixture. Sprinkle the chili powder, cumin, dried cilantro, salt, and black pepper over the chicken and onion. Stir well to coat everything evenly.

Add the pasta and liquid ingredients. Stir in the minced garlic, elbow macaroni, chicken broth, the entire can of Rotel (with its juices), and the tomato sauce. Stir until combined. Bring the mixture to a gentle boil.

Simmer until the pasta is cooked. Reduce the heat to medium-low. Cover the skillet and let it cook for about 12 minutes, stirring once halfway through. Cook until the pasta is tender and most of the liquid has been absorbed.

Add the cheese and milk. Stir in the shredded Colby Jack cheese and the milk. Continue stirring until the cheese is fully melted and the sauce becomes creamy.

Finish and serve. Garnish the finished pasta with fresh chopped cilantro. Serve immediately while warm.