Bring a large pot of salted water to a boil. Add the fettuccine pasta and cook according to package instructions until al dente. Drain the pasta and set it aside while you prepare the sauce and chicken.
In a large skillet, heat 1 tablespoon of olive oil over medium-high heat. Add the diced chicken breasts, season with salt, pepper, and Italian seasoning, and cook until the chicken is no longer pink and starts to brown, about 5-7 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the sliced mushrooms and minced garlic. Sauté until the mushrooms are golden and tender, about 5 minutes. The garlic will become fragrant and add a wonderful aroma.
Reduce the heat to medium and pour in the heavy cream and chicken broth. Stir well, scraping up any browned bits from the bottom of the skillet for extra flavor. Let the mixture simmer for 3-4 minutes until it begins to thicken slightly.
Stir in the grated Parmesan cheese until the sauce is smooth and creamy. Season with additional salt and pepper to taste.
Return the cooked chicken to the skillet with the mushroom Alfredo sauce. Add the drained fettuccine pasta and gently toss everything together until the noodles are thoroughly coated with the creamy sauce and the chicken and mushrooms are evenly distributed.
Preheat your oven to 375°F (190°C). Pour the pasta mixture into a greased 9x13 inch baking dish. Sprinkle the shredded mozzarella cheese evenly over the top for that irresistible cheesy crust.
Bake uncovered for 20-25 minutes, or until the cheese is melted, bubbly, and golden brown on top.
Remove from the oven and let it rest for a few minutes before serving. Garnish with freshly chopped parsley for a pop of color and fresh flavor. Grab a fork and enjoy the ultimate creamy comfort food!