Preheat the Oven: Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish to prevent sticking.

Sauté the Aromatics: In a large skillet, heat olive oil over medium heat. Add diced onion and minced garlic, cooking until translucent and fragrant, about 3-4 minutes.

Prepare the Chicken Mixture: Add the shredded chicken to the skillet with the sautéed onion and garlic. Warm through and set aside.

Mix the Ricotta Layer: In a medium bowl, combine ricotta cheese, 1/2 cup Parmesan cheese, egg, chopped basil, and parsley. Season with salt and pepper, and stir until well combined.

Assemble the Lasagna: Spread a thin layer of béchamel or Alfredo sauce over the bottom of the baking dish. Lay down 3 lasagna noodles. Spread half of the ricotta mixture over the noodles, top with half of the chicken mixture, then sprinkle 1 cup of mozzarella cheese over the chicken. Pour a third of the remaining sauce over the cheese. Repeat for the second layer.

Final Layer and Baking: Place the last 3 noodles on top. Spread the remaining sauce, sprinkle with remaining mozzarella and Parmesan cheese, and a pinch of nutmeg (if using). Cover with foil and bake for 25 minutes.

Uncover and Finish Baking: Remove the foil and bake for an additional 10-15 minutes until the top is bubbly and golden brown.

Let It Rest and Serve: Allow the lasagna to rest for 10 minutes before cutting into it to set the layers. Serve hot.