Bring a large pot of salted water to a boil. Add the 8 oz of elbow macaroni and cook until al dente, usually around 7 to 8 minutes. Drain and set aside.
Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the diced chicken breast along with 1 teaspoon each of garlic powder, onion powder, and chili powder. Season with salt and pepper to taste. Sauté the chicken until fully cooked and lightly browned, about 6 to 8 minutes.
In the same skillet, pour in 1 cup of chicken broth and bring to a gentle simmer. Lower the heat and whisk in the cream cheese and milk until smooth and creamy. Gradually add the shredded cheddar and Monterey Jack cheeses, stirring constantly until the cheese has fully melted and the sauce is luscious and velvety.
Add the cooked elbow macaroni and sautéed chicken into the cheese sauce. Stir thoroughly to coat every piece of pasta and chicken evenly with that rich queso goodness. Adjust seasoning with salt and pepper if needed.
Transfer your Cheesy Chicken Queso Macaroni to a serving dish and sprinkle liberally with chopped green onions. Serve immediately.