Boil a large pot of salted water and cook lasagna noodles al dente, about 8-10 minutes. Drain and lay flat on a towel.

In a mixing bowl, combine cooked chicken, softened cream cheese, shredded mozzarella, and diced Hatch green chiles. Mix well and season with salt and pepper.

In a skillet, melt butter over medium heat. Whisk in flour to form a roux. Gradually add milk while whisking. Cook until thickened, then stir in Parmesan cheese.

Preheat oven to 350°F. In a baking dish, layer with white sauce, noodles, chicken filling, and repeat layers, finishing with noodles and sauce topped with mozzarella.

Cover with foil and bake for 30-45 minutes. Remove foil and broil for 2-3 minutes to brown cheese.

Let rest for 10-15 minutes before serving.