Preheat oven to 350 degrees. Spray a 9-inch deep dish pie pan with cooking spray.
Warm the enchilada sauce in a small skillet over low heat until just warm. Dip corn tortillas in the sauce then place around the sides of the pie plate coming up the edge. Place one dipped tortilla on the bottom of the pie plate. Save the rest of the sauce.
Whisk the eggs in a large bowl. Add the half and half and whisk to blend. Stir in the green chilies, pimentos, green onions and 1½ cups of cheese. Pour into the pie plate. Sprinkle the remaining cheese over the top of the quiche and bake for 50-60 minutes or until the center is set. If the tortilla crust starts getting to brown, place a piece of foil over the top.
Remove the quiche from the oven and let set 5-10 minutes before serving. Bring the remaining sauce to a boil and reduce by half. Drizzle over the top of the quiche. Serve with sour cream if desired.