Preheat oven to 425 degrees. Line a baking sheet with a silicon baking mat or parchment paper. Roast the sweet potato for 20-25 minutes, until tender.
Reduce oven to 350.
Meanwhile, make the cheese sauce. Put the potato and carrot cubes in a pot and fully cover with water. Boil for 10 minutes, until soft. Remove the carrot and potato pieces from the water with a sieve or colander, then add to your blender with the cashews, water, nutritional yeast, salt, yellow mustard, and half the green chillies. Blend until smooth and creamy. Add the remaining green chilies and pulse once or twice so they mix throughout.
Pour the cheese sauce into a bowl and rinse out the blender.
Make your enchilada sauce. Toss all the enchilada sauce ingredients in the blender and blend until smooth.
Make the filling. In a bowl mix together the roasted sweet potato, kale, and black beans.
Assemble the pie. Add a small layer of enchilada to the bottom of the pie pan. Add one tortilla, then top it with a little more enchilada sauce, coating it completely. Add half the filling, then dollops of nacho cheese. Repeat until all layers are done.
Top the pie with more enchilada sauce and a sprinkling of vegan cheese (if desired). Bake uncovered for 25 minutes.
Sprinkle the pie with cilantro, avocado, and serve with lime slices. Enjoy!