If you’d prefer to have chunks of chicken stirred into the macaroni, cut them into ½-inch pieces before cooking.
Cook the pasta according to package directions; drain well.
Cook the bacon in a large deep skillet over medium-high heat until crisp; remove bacon with a slotted spoon and set aside. Drain fat from the pan, reserving 1 tablespoon fat.
Season the chicken with smoked paprika, oregano, salt and pepper. Sauté the chicken in the bacon fat for about 8 minutes or until no longer pink in center and nicely browned. Set aside.
Heat oil in the skillet over medium heat; sauté onion and garlic for about 3 minutes or until tender. Stir in the flour until well combined; stir in the tomato paste. Pour in milk; cook and stir for 5 minutes or until thickened and bubbly. Stir in the cheese and cook for 3 minutes or until the melted and pasta is well coated.
Spoon the cooked pasta into the cheese sauce; stir until well coated. Spoon into a casserole serving dish and top with sliced chicken, sprinkled with the bacon and parsley. Or serve in individual bowls. topped with the chicken, bacon, and parsley.