Preheat your oven to 375°F (190°C).Bring a large pot of salted water to a boil. Cook the macaroni according to the package instructions until al dente. Drain and set aside.
In a large skillet or frying pan, heat the olive oil over medium heat. Add the diced chicken and cook until browned and cooked through, about 6-8 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the chopped onion and minced garlic. Sauté until the onion becomes translucent and fragrant, about 2-3 minutes.
In a separate bowl, whisk together the chicken broth, milk, all-purpose flour, dried thyme, and dried basil until well combined.
Pour the broth mixture into the skillet with the onions and garlic. Cook over medium heat, stirring constantly, until the sauce thickens and comes to a simmer.
Reduce the heat to low and add the shredded cheddar cheese to the sauce. Stir until the cheese is melted and the sauce is smooth.Season the sauce with salt and pepper to taste.
Add the cooked chicken and macaroni to the skillet with the cheese sauce. Stir until everything is well coated.
Transfer the mixture to a greased baking dish and spread it evenly. Bake in the preheated oven for about 20 minutes or until the top is golden and bubbly.
Remove from the oven and let it cool for a few minutes before serving.
Garnish with fresh parsley, if desired, and serve hot.