Season the chicken: Pat chicken dry. Sprinkle both sides with garlic powder, Italian seasoning, salt, and pepper.
Cook the chicken: Heat olive oil in a large skillet over medium heat. Cook chicken 5–6 minutes per side until golden and fully cooked. Transfer to a plate to rest.
Boil the pasta: Cook fettuccine in salted boiling water according to package directions. Reserve ½ cup pasta water, then drain.
Make the Alfredo sauce: In the same skillet, sauté minced garlic for 30 seconds. Pour in heavy cream and bring to a gentle simmer.
Add the cheese: Stir in Parmesan until sauce is smooth and creamy. If too thick, add a splash of reserved pasta water.
Combine: Toss pasta in the sauce until coated. Slice chicken and place on top.
Serve: Garnish with parsley if desired. Serve immediately.