Preheat your oven to 350°F.
In a bowl, whisk the eggs with milk, salt, and pepper.
Coat a large skillet with cooking spray and pour in the egg mixture, cooking over medium heat while stirring until the eggs are thick and no liquid remains, then remove them from the pan.
In the same skillet, cook and crumble the sausage over medium heat until fully cooked and no longer pink, about 5 to 7 minutes, then drain the grease.
In another bowl, stir together the sour cream and condensed soup.
Spread half of this mixture into an ungreased 13x9-inch baking dish.
Begin layering with half of the tortilla pieces, then add half the salsa, all the scrambled eggs, the cooked sausage, and the remaining tortilla pieces.
Spread on the rest of the sour cream mixture, top with the remaining salsa, and sprinkle generously with shredded cheeses.
Bake uncovered for 30 to 35 minutes or until heated through.
If you like, serve with enchilada sauce and sliced green onions on top.