Step 1

Arrange a rack in the middle of the oven and heat to 375°F.

Step 2

Lightly coat a 13x9-inch baking dish with cooking spray. Add the shredded potatoes (break up any large clumps with your hands), beans, and chiles. Stir to combine, then spread into an even layer.

Step 3

Whisk the eggs, sour cream, milk, cheese, salt, and pepper in a large bowl. Pour over the vegetable mixture.

Step 4

Bake until the top is light golden-brown and a knife inserted in the center comes out clean, about 45 minutes. Let cool for 5 minutes before slicing. Serve with sliced avocado, fresh cilantro, and salsa, if desired.