Wash and peel the sweet potatoes. Cut into bite-size cubes.
In a cast iron frying pan over medium heat, heat the olive oil. Toss in the cubed sweet potatoes, salt, pepper, paprika, cumin, and garlic powder. Stir to combine and let cook for 20-25 minutes, stirring occasionally, until a fork can go through one with little to no resistance. Remove from heat.
Finely dice the onions and set aside.
Mince the chipotle pepper. In a small bowl, combine the sour cream, heavy cream, lime juice, minced chipotle pepper, and minced garlic. Stir to combine.
Assemble the tacos in this order: tortilla, sweet potatoes, black beans, onion, chipotle crema dressing. Serve with pico de gallo (or salsa) and chips.
Recipe by Natural Chow at http://naturalchow.com/2015/03/chipotle-sweet-potato-black-bean-tacos/