Cook the noodles. Bring a large pot of salted water to a boil. Cook lasagna noodles until just al dente, about 8–9 minutes. Drain and lay flat on parchment or lightly oiled foil so they don’t stick.
Make the Alfredo sauce. In a medium saucepan, melt butter over medium heat.
Add garlic and cook 30–60 seconds until fragrant. Whisk in flour and cook 1 minute. Slowly whisk in milk and cream.
Simmer 3–4 minutes until slightly thickened. Stir in Parmesan, nutmeg, salt, and pepper. Remove from heat.
Mix the filling. In a bowl, combine ricotta, 1 cup mozzarella, 1/2 cup Parmesan, egg, spinach, parsley, garlic powder, onion powder, Italian seasoning, salt, and pepper.
Fold in the chicken until evenly distributed.
Preheat and prep the pan. Heat oven to 375°F (190°C). Spread 1 cup of Alfredo sauce over the bottom of a 9x13-inch baking dish.
Assemble the roll ups. Spread about 1/4 cup of filling evenly over each noodle, leaving a small border at the ends. Roll up gently from the short end.
Place seam-side down in the sauced baking dish.
Sauce and top. Spoon remaining Alfredo sauce over the roll ups. Sprinkle the remaining 1/2 cup mozzarella and a bit more Parmesan on top.
Bake. Cover loosely with foil and bake 20 minutes. Uncover and bake 8–10 more minutes until bubbly and lightly golden.
Rest and serve. Let sit 5–10 minutes to set.
Garnish with fresh parsley and extra Parmesan. Serve warm.