Preheat oven to 400. Line baking dish with aluminum foil and set aside.
In a preheated pan on medium heat melt coconut oil. Add tomatillos, onion, and half of jalapeño. Cook until a thin sauce forms. Add chicken and heat through. Season with salt and pepper to taste.
Using one tortilla at a time, add 2 tablespoons sauce, top with a few spoonfuls of tomatillo chicken, and a sprinkle of cheese. Wrap and transfer to baking dish. Repeat with remaining tomatillo chicken, cheese, and tortillas.
Once all tortillas are wrapped and placed in baking dish, cover with enchilada sauce. Spread sauce around.
Sprinkle enchiladas with remaining cheese and jalapeño. Transfer to oven and bake for 15 minutes, until golden and bubbly.