Make the enchilada sauce: In a large bowl, cover the dried chiles with the hot water. Cover the bowl with plastic wrap and let the chiles soak for 20 minutes.
Transfer 1/2 cup of the chili water and the chilis to a blender. Add 1/2 cup water and the tomato paste, cocoa powder, Erythritol, garlic powder, cumin, onion powder, oregano, cinnamon, 1 teaspoon salt and 1/2 teaspoon pepper. Puree for 1 minute. Add the olive oil and puree until smooth, adding more water to achieve a pourable sauce consistency. Season to taste with salt and pepper, then set aside
Make the enchiladas: Prepare a large bowl of ice water. Line a baking sheet with a clean dish towel. Bring a large pot of water to boil over medium-high heat. Place 2 cabbage leaves at a time in the boiling water for 1 minute. Remove and transfer to the bowl of ice water. When cool enough to handle, transfer the leaves to the towel-lined tray to drain. Continue with the remaining cabbage leaves. Set aside.
Season the chicken thighs all over with 1 teaspoon salt and 1/2 teaspoon pepper. Heat the olive oil in a large skillet over medium-high heat, add the chicken thighs and cook until browned, turning once halfway through cooking, 8 to 10 minutes. Transfer to a plate; set aside.
Lower the skillet heat to medium, add the butter, celery, white and light green parts of the scallion, and the garlic powder, ground cumin, onion powder, dried oregano, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Cook until celery softens a bit and the spices are fragrant, for 4 to 5 minutes. Add the green chiles and toss to combine. Remove the skillet from the heat and add the cream cheese in small pieces, stirring so it melts in.
Preheat the oven to 350°F (177°C). Finely chop the cooled chicken and add it and any residual juices into the skillet along with 1/2 cup of the grated cheese. Stir to combine.
Spread 1/3 cup of the enchilada sauce into a 10-inch square or 9 by 12-inch baking dish. Working one at a time, spoon about ⅓ cup of the chicken mixture (enchilada filling) into the center of a blanched, drained cabbage leaf. Roll up it up like a cigar, fold over the top and bottom edges toward the seam, then place it, seam side down into the baking dish Repeat with all the leaves and filling to the enchiladas are in one layer. Spoon the remaining sauce over the enchiladas.
Bake, uncovered, in the oven until heated through, about 20 minutes. Sprinkle with the remaining cheese, then return to the oven for 10 minutes. Remove from the oven and let the enchiladas stand for 5 minutes before serving. Garnish with the dark green scallion slices and enjoy.