Make filling by mixing chicken and the sour cream, chopped onions and the shredded cheddar and jack cheeses (reserve 1/4 cup each for later). Spread 1/2 cup green sauce (salsa Verde), in baking dish and warm remaining sauce in pan. Warm tortillas on skillet or wrap in foil and heat in oven til soft.Dip in warm sauce, remove at once and place in baking tray.
Spread 1/2 cup filling down center of each tortilla.Wrap tortilla around filling to form enchilada and put seam side down in baking tray. Cover with remaining sauce and reserved cheese. Top with olives. Preheat oven to 350 and bake 15 minutes.
Beans and rice will go well with this dish.Enchilada sauce can be used instead of green sauce.