Preheat the oven to 375º F and adjust the rack to the middle position. Melt the butter in a large skillet over medium heat. Add the onion, bell pepper, poblanos and jalapeño to the pan. Cook for about 8-10 minutes, until softened. Stir in the garlic, chili powder, cumin, and salt and cook for 1 minute.
Sprinkle the coconut flour over the vegetable mixture and cook for 1 minute while stirring continuously. Stir in the stock and bring to a simmer. Simmer for 4 minutes. Remove from the heat and stir in the tomatoes, chilis and sour cream.
Place the chicken and cilantro in a large bowl. Pour the vegetable mixture over top and stir until combined.
Place 8 crepes on the bottom of a 13×9 – inch buttered casserole dish. Top the crepes with half of the chicken mixture and then half of the cheese. Repeat with remaining ingredients. Bake for 45-50 minutes until cheese is bubbly and the edges of the casserole are just turning golden brown. Let stand 10 minutes before serving.