Heat oven to 400 degree F. Coat a 10-inch springform pan with nonstick cooking spray.
Heat oil in a large nonstick skillet over medium heat. Add potatoes and cook, stirring occasionally, for 12 minutes or until tender. Add chili powder, 1/3 cup of the scallions and 1/4 teaspoon of the salt. Cook 2 minutes. Spoon into a bowl.
Wipe out skillet. Coat with nonstick cooking spray. Beat eggs, egg whites, Mexicorn, black pepper and remaining salt. Add to skillet; cook over medium heat for 2 to 3 minutes or until just set, stirring continuously. Spoon into another bowl.
Wipe out skillet and spray with cooking spray. Remove casings from sausage and add to skillet along with red pepper and the remaining scallions. Cook for 6 minutes, breaking up sausage with a spoon. Stir in 1/4 cup of the salsa. Take off the heat.
Place a tortilla in the bottom of the prepared pan. Spread potatoes over the tortilla in an even layer. Top with a tortilla. Spread on half of the sausage mixture. Top with a tortilla, egg mixture, tortilla, remaining sausage mixture and tortilla. Spoon on remaining salsa. Sprinkle with Monterey Jack cheese.
Bake at 400 degree F for 40 minutes. Tent loosely with foil during the last 20 minutes. Remove from oven and remove foil. Let stand 10 minutes. Run knife around edge. Remove side of pan; slice into 8 portions. Serve with sour cream. Makes 8 servings.