Preheat the oven to 375°F. Grease a 9x11 baking dish with cooking spray or olive oil. To make the sauce, combine the onion, cilantro and garlic in the bowl with a spatula, and blend for another 7 seconds, until very finely chopped and almost smooth.
Heat the olive oil in a large sauté pan or Dutch oven over medium-high heat. Add the onion mixture, the coriander, chili powder, cumin and salt and cook for 5 minutes, or until the liquid has evaporated and the mixture starts to brown.
Meanwhile, in a food processor, combine the tomatoes, chipotles and adobo sauce and process until smooth. Pour the tomato mixture into the pan with the onion mixture, bring to a boil, then reduce the heat to maintain a simmer and cook for 10 minutes more.
To make the enchiladas, in a bowl, combine the shredded chicken, oregano, onion, 1/2 cup of shredded cheese and 1/2 cup sauce to the chicken mixture and stir to combine. Taste the filling and add salt if necessary (some rotisserie chickens are saltier than others).
Pour half the remaining sauce into the prepared baking dish, using a spatula to spread it evenly over the bottom of the dish. Place a spelt or flour tortilla on a flat surface, fill it with one-eighth of the chicken mixture, carefully roll it u, and place it seam-side down in the baking dish. Repeat with the remaining tortillas and filling, and then pour the remaining sauce over the top, using a spatula to spread evenly.
Cover the dish with aluminum foil and bake for 15 minutes. Remove the foil, sprinkle the remaining 1/2 cup shredded cheese and 1/2 cup queso fresco evenly over the enchiladas, and return to the oven for 10 to 15 minutes, or until the cheese has melted and the sauce is bubbling.
Finish the enchiladas under the broiler to brown the cheese, if desired.