Make Pork Carnitas recipe (link in text above) a day ahead or start in the morning and prepare enchiladas in the evening.
Make enchilada sauce recipe (link above) and set aside.
Peel and cut sweet potatoes into 1/2" pieces. Place on a baking tray with oil and spices. Bake potatoes at 400°F for 15 minutes, stirring once halfway. Set aside to get ready for assembly.
Pour about 1/2 cup enchilada sauce onto a plate.
Cover bottom of a 9"x13" baking dish with a thin layer of enchilada sauce as well.
Place one tortilla on the plate with sauce and flip so it's fully covered in sauce. (This gets messy, but it's definitely the easiest and quickest way!)
Add carnitas, sweet potatoes, black beans, green chiles and any other toppings you want.
Roll up and place seam side down in the 9"x13" baking dish.
Cover with extra sauce and 1 cup of cheese, or more to taste. Cover with foil and bake for 20 minutes. Uncover and bake another 5 minutes until cheese is melted and bubbly.