Preheat over to 350 degrees F.
Lightly spray an 11x7 baking dish with non-stick spray.
De-seed each fresh green chile (or lay out the canned green chiles on a paper towel).
Cut one slice of Monterey Jack cheese for each chile, and stuff it inside. Arrange each chile evenly in the baking dish.
Whisk together the eggs, flour, and milk, and pour the mixture over the chiles in the baking dish.
Sprinkle the shredded cheese, chile powder, and green onions on top of the chile and egg mixture.
Bake casserole for 35 minutes, or until a toothpick inserted in the middle comes out clean (oil from the cheese is ok, but raw egg is not!)
Cut into 4 portions, top with salsa, and serve!
