Heat olive oil in a large skillet or Dutch oven over medium-high heat
Add the garlic and saute one minute, stirring occasionally
Sprinkle with the flour and stir to combine, continue to stir and cook for 2 minutes to cook the flour
Add the chicken broth and whisk until mixture starts to thicken, add milk and continue to cook and whisk until thickened
Stir in parmesan cheese, salt, and pepper
Remove from heat and add chicken
Pour mixture over the ziti and gently stir to combine
Pour half of the mixture into a greased 9 X 13 baking dish
Sprinkle evenly with half of the mozzarella cheese, layer the remaining pasta mixture evenly on top and add the remaining cheese evenly over the top of the pasta.
Bake uncovered in a 375-degree oven for 25 minutes until cheese is melted and the top just starts to turn a golden brown
Sprinkle with chopped parsley and serve!