Preheat your oven to 400°F (200°C) and lightly grease a 9x13-inch baking dish.

In a large pot, bring salted water to a boil and cook the pasta until 2 minutes shy of package instructions. Drain and set aside.

In a large skillet, heat olive oil over medium-high heat and sauté the seasoned chicken for 5-6 minutes until fully cooked.

In the same skillet, melt butter over medium heat, add garlic, and sauté for about 30 seconds.

Stir in heavy cream and whole milk; let simmer until slightly thickened, about 2-3 minutes.

Add pesto and Parmesan cheese; stir until melted and smooth.

Combine cooked pasta and sautéed chicken into the skillet, adding spinach if desired, and toss gently.

Transfer the mixture to the baking dish. Top with mozzarella and extra Parmesan.

Bake uncovered for 20-25 minutes until cheese is golden and bubbly.

Let the dish rest for about 5 minutes before serving.