Start by boiling salted water in a large pot and cook the pasta until al dente. Reserve some pasta water before draining, as it helps adjust the sauce later. Set the cooked pasta aside while preparing the rest.
Heat olive oil in a skillet over medium heat and add sliced chicken. Season it with salt, pepper, and Italian seasoning, then cook until golden and fully done. Remove the chicken and keep it aside to retain its juices.
In the same pan, sauté minced garlic until fragrant, then pour in the heavy cream. Stir gently and let it simmer until slightly thickened, creating a rich base for the sauce.
Mix in the pesto and freshly grated Parmesan cheese into the cream. Stir until the cheese melts completely and the sauce becomes smooth and flavorful.
Return the cooked chicken to the pan and add the drained pasta. Toss everything together, adding reserved pasta water little by little until the sauce coats the pasta perfectly.
Let the pasta cook together for a minute so flavors blend well. Taste and adjust seasoning if needed, then serve warm with extra Parmesan on top.