To make Sauce:
1. In a large 4 quart sauce pan bring 4 cups of water to a boil. Add the tomatoes and the garlic and cook for 20 minutes. Meanwhile, in a separate skillet heat 1 t. of olive oil and saute the onions until soft. In the boiling water the tomato skins should start to peel off on their own. After 20 minutes remove the tomatoes and strip them of their skins.
2. Place the peeled tomatoes, garlic cloves, softened onions, chilies, salt, vegetable stock and oregano in a blender with about ½ c. of the cooking water. Blend well. Taste it with a spoon and add more salt or chilies as needed.
3. Pour sauce back into the sauce pan and cook for another 15-20 minutes on a low simmer, it will thicken up slightly and can be used right away, or stored for up to 3 days in the fridge in a sealed container.

To Assemble Enchiladas:
1. Preheat the oven to 350ºF. Brush the bottom of a 9×13 baking dish lightly with olive oil.
2. Carve the rotisserie chicken and shred the meat with the tines of a fork until the strips are small enough to be wrapped in a tortilla.
3. Lay a tortilla on the counter, place a small pile of meat on it, then drizzle with a Tablespoon of Ranchero sauce and sprinkle with cheese. Roll up the tortilla and place it, opening side down, in the baking dish. Repeat until baking dish is totally full. This usually makes about 14 enchiladas when I make it.
4. Pour 1 ½ c. of Ranchero Sauce over the enchiladas and sprinkle with remaining shredded cheese.  If making ahead, at this point the enchiladas can be covered with plastic and placed in the fridge until dinner time.
5. Bake at 350ºF for 35 minutes, or until top is bubbly. Serve hot.