In a small bowl, mix together the garlic powder, onion powder, cumin, smoked paprika, chili powder, salt, and pepper. Season the chicken on both sides using the spice mix.
Heat a medium sauce pot or skillet to medium-hot. Coat the bottom of the pan with avocado oil. Add the chicken, searing the thighs on each side until they're golden brown. This should take about 3-5 minutes each side. Add the chicken broth and reduce heat to low. Partially cover the pot with a lid and let the chicken simmer on a very low bubble for 30 minutes more. Once chicken is done, remove it to a plate, to let it cool slightly. Then use two forks to shred the chicken off the bone. Pour the chicken stock from the pan into a heat-safe bowl and set it aside.
Heat that same pan over medium-high heat and drizzle the pan with avocado oil. There may still be some brown bits and seasoning on the bottom of the pan from the chicken and thats ok. Add the cubed butternut squash and stir. Cover the pan with a lid and let the squash cook down for 10-15 minutes, stirring every few minutes.
Once the squash is very golden-brown, add the reserved chicken stock that you had set aside. Heat the stock until it bubbles and scrape the bottom of the pan with a wooden spoon if there are any brown bits.
Add the chicken, black beans, and a few tablespoons of the chopped cilantro to the squash. Stir and remove from heat.
Preheat oven to 350ºF. Wrap your tortillas in a damp paper towel and microwave them on high for approximately 30 seconds or until they're pliable. If using cassava flour tortillas, you may need to heat the tortillas on each side in a skillet because the tortillas are too delicate and/or sticky for the microwave. Keep them warm while you work by wrapping them in a warm, damp towel.
Coat the bottom and sides of a 9x13 baking dish with 1 tbsp of avocado oil. Then coat the bottom of the pan with 1/2 cup of the enchilada sauce (a very thin layer, but make sure the bottom is coated).
To assemble: on a cutting board, lay one warm tortilla flat and place 1/4 cup of the butternut squash filling into one half of the tortilla. Roll the tortilla up, making sure to keep the filling tightly stuffed. Place the tortilla in the prepared pan, seam side down. Repeat with remaining tortillas.
Pour remaining enchilada sauce over the top of the tortillas and sprinkle with cheese. Bake for 25-30 minutes. Remove from oven and allow to cool for 5 minutes before serving.
Serve with sautéed peppers and onions or a sliced cabbage side salad, if desired. Top with avocado slices, more cilantro, and fresh lime juice! Enjoy!