Preheat your oven to 375°F (190°C).
In a skillet, heat olive oil over medium heat. Add minced garlic and cook until fragrant.
Add shredded chicken, salt, and pepper to the skillet. Cook for 5-7 minutes, then set aside.
In a mixing bowl, combine ricotta cheese, spinach, and half of the Parmesan cheese.
Layer the bottom of a baking dish with butternut squash slices.
Spread a layer of the ricotta mixture over the squash, followed by a layer of the chicken mixture.
Sprinkle a layer of mozzarella cheese over the chicken.
Repeat layers until all ingredients are used, finishing with a layer of mozzarella and the remaining Parmesan cheese on top.
Cover the dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 15 minutes, or until the cheese is golden and bubbly.
Let the lasagna cool for 10 minutes before serving.