Peel the sweet potatoes and cut into lengthwise quarters. Cut each of the slices into bite-sized cubes. Add to a bowl and toss with 2 tablespoons olive oil and 1 teaspoon each of cumin, chili powder, and garlic powder + 1/2 t. salt.
Spread the seasoned potato cubes onto a cookie sheet and bake at 375° for 10 - 15 minutes, until crisped and browned.
If you're meal prepping the potatoes, put them in the refrigerator at this point. Otherwise proceed to the next step.
Dice the red onion and mince the garlic cloves. Heat 1 tablespoon of olive oil in a large skillet over medium-low heat and add the onion and garlic.
Cook until the onion is translucent, about 5 minutes, and then stir in the remaining cumin, chili powder and salt. Cook for one minute, stirring frequently.
Add the cooked sweet potatoes and black beans to the skillet. Squeeze the lime over the potato and bean mixture and then stir in the diced chiles and cilantro. Cook for 3 minutes, just until combined and heated through.
While the sweet potatoes and black beans are cooking, place 12 corn tortillas on cookie sheets and back at 375° for 3 to 5 minutes, until they are starting to get crispy.
Remove tortillas from the oven, flip each tortilla over and then top each with an equal amount of the sweet potato and black bean filling. Place back in the oven for 3 to 5 minutes, until crispy and hot.
Serve with your favorite toppings and enjoy!