Preheat oven to 350 degrees.
Cut the zucchini in half and scoop out most of the flesh, leaving about 1/4 inch thick wall. Chop up the scooped out zucchini. Set aside.
In a large pot, bring 4 quarts of salted water to a boil. Add the zucchini halves and cook for 1 minute. Remove and drain the halves well.
Meanwhile, in a large skillet, heat olive oil. Add onion, garlic, chopped zucchini, chili powder, cumin, oregano, salt and pepper and cook until onions are soft, about 5-7 minutes. Add chicken, and Ortega chiles.
Pour a few tablespoons of enchilada sauce in the bottom of a 15 X 10-inch baking dish and spread to cover the bottom. Lay zucchini halves cut side up, in a single layer. Fill each zucchini half with about a heaping 1/4 cup of the filling, the firmly pressing down on it to stabilize.
Pour the remaining enchilada sauce evenly over stuffed zucchini. Cover tightly with aluminum foil and bake in preheated oven for 3o minutes. Uncover and evenly sprinkle cheese over zucchini. Place bake in the oven and continue to cook until cheese is melted and zucchini is tender.