01 - Preheat the oven to 375°F. Grease a 9x13-inch baking dish with butter or nonstick spray.
02 - Cook lasagna noodles according to package instructions until al dente. Drain, rinse lightly with cool water, and lay each noodle flat on a baking sheet or clean kitchen towel to prevent sticking.
03 - In a large mixing bowl, combine the shredded chicken, ricotta, 1 cup mozzarella, 1/2 cup Parmesan, minced garlic, parsley, egg, salt, and black pepper. Stir until evenly incorporated.
04 - Melt the butter in a medium saucepan over medium heat. Whisk in the flour and cook for 1 minute to form a roux. Gradually pour in the milk while whisking constantly. Continue cooking and whisking until the mixture thickens, about 3 to 4 minutes. Stir in 1/2 cup Parmesan and garlic powder. Season with salt and pepper to taste. Remove from heat.
05 - Spread 1/2 cup of marinara sauce evenly across the bottom of the prepared baking dish.
06 - Lay each cooked noodle flat. Spread 2 to 3 tablespoons of the chicken filling evenly over each noodle. Roll each noodle up tightly from one end to the other.
07 - Place the roll ups seam-side down in the baking dish atop the marinara base. Pour the creamy Parmesan sauce over the roll ups, then drizzle the remaining marinara sauce on top.
08 - Sprinkle 1 cup shredded mozzarella and 1/2 cup grated Parmesan evenly over the top of the assembled roll ups.
09 - Bake for 30 to 35 minutes until the cheese is bubbly and golden brown on top. Allow the dish to rest for 5 to 10 minutes before serving.