Preheat oven to 375˚F and spray an 8x8 baking dish with nonstick cooking spray and set aside.
Drain chilies and slice them in half lengthwise, and then in half lengthwise again. Arrange half of the chilies on the bottom of the prepared baking dish and top with 1/2 cup of cheddar and 1/2 cup pepper jack cheese. Repeat layer with remaining chilies and another 1/2 cup of both cheeses.
In a medium mix bowl whisk together evaporated milk, eggs, egg white, chile paste, flour, garlic salt, and pepper. Pour egg batter over chilies and top with the salsa verde and remaining cheese.
Bake for 40 minutes. Garnish with diced jalapeños, fresh chopped cilantro, and sliced avocados.