Boil a large pot of water. Salt the water and cook pasta according to package directions.
Slice each chicken breast in half lengthwise for faster cooking. Season with 1 teaspoon of salt, garlic powder and black pepper.
Heat up the olive oil in a large skillet to medium high heat. Add the seasoned chicken breast and cook for about 4-5 minutes on each side until fully cooked. Set aside to cool.
Using the same skillet you cooked the chicken in, add the butter and melt over medium heat. Once the butter has melted, add the flour and whisk for 30 seconds.
Heat up the milk in a small saucepan or in microwave for about 1-2 minutes until almost boiling. Slowly add the warm milk to the skillet and whisk thoroughly until the flour/butter mixture fully dissolves.
Add the cold cream to the milk mixture and whisk for 2 minutes until sauce is thickened. Add 1 teaspoon of salt, nutmeg and white pepper and whisk together.
Slice the cooked chicken into ½ inch slices and add to sauce along with the cooked pasta. Mix to combine. If the skillet is not ovenproof, empty pasta mixture to an oven-safe casserole dish and top with the shredded mozzarella. Bake for 30 minutes until cheese is melted and bubbly.
Garnish with chopped parsley and serve warm. (Optional)