Preheat a broiler or air-fryer to high. Place all the peppers, the roughly chopped onion, the tomatillos, and the garlic on a sheet tray. Broil or air-fry until the vegetables are softened and deeply charred, 5-10 minutes.
Transfer all the roasted vegetables to a blender. Add half the cilantro and blend until smooth. Season to taste with salt. Add a splash of stock or water if the sauce is too thick.
In a large bowl, combine the turkey (or chicken), half of the cheese, the remaining cilantro, and 1 ½ cups of the sauce. Toss to combine and season to taste with salt.
Heat the oil in a small skillet to around 375°F. Fry the tortillas one at a time until bubbling but not crisp, about 5 seconds per side.
Preheat the oven to 375°F. Spread a thin layer of sauce over the bottom of a baking dish. Add a few tablespoons of the filling mixture in a line down the center of each tortilla, roll it up, and nestle into the baking dish.
Spoon a line of the remaining sauce over the enchiladas, sprinkle the remaining cheese on top, then add another line of sauce on top of the cheese.
Bake until the cheese is bubbling and the edges are browned and crisp, 20 to 25 minutes. Remove from oven, sprinkle with reserved sliced onions and cilantro, and serve.
