1. Preheat oven to 325 degrees F and spray a 13x9-inch baking dish with nonstick spray. Set aside.

For the Creamy Sauce

1. In a medium sauce pan, cook the flour and butter over medium heat, stirring into a bubbling paste for about 2 minutes.
2. Whisk in LACTAID® Reduced Fat 2% Lactose-Free Milk and cook over medium heat, stirring very frequently, until the sauce begins to thicken, about 7 minutes. Season with salt and pepper.

For the Green Sauce

1. In a medium sauce pan, cook the onion in oil over medium heat until soft, about five minutes.
2. Add the garlic and chilies, and cook until fragrant, about another minute.
3. Add the chicken stock and remove from heat (mixture will be just warm).
4. Pour into blender and pulse into a smooth sauce.
5. Pour back into the pan, season with salt and pepper, and set aside.

For the Filling

1. In a medium bowl, mix the chicken, LACTAID® Cottage Cheese and salsa. Taste before seasoning with salt and pepper.

For the Assembly

1. Wrap the tortillas in damp paper towels and microwave for 15 seconds to soften.
2. Working one at a time, dip each tortilla in the green sauce and then fill with a few tablespoons of chicken filling, and then place seam side down in the baking dish. Repeat with the remaining tortillas.
3. Pour the remaining green sauce and the creamy sauce on top of the enchiladas.
4. Bake until bubbly and starting to turn golden brown on top, about 30 minutes.
5. Let cool 10 minutes before topping with avocado, tomato and cilantro (if using), and serve.