Preheat your oven to 400°F.
In a large pan, heat a generous amount of olive oil over medium heat. Add the cubed sweet potato, cover, and cook for about 15 minutes, stirring every few minutes until tender and lightly browned.
Stir in the seasonings and mix well. Add the red onion and a little more olive oil (if needed). Sauté uncovered until the onion is softened and everything is nicely golden. Stir in the drained black beans and cook for 1–2 minutes, just until warmed through. Remove from heat and set aside.
Line a baking sheet with parchment paper. Place the tortillas on the sheet and brush both sides with olive oil. Add the sweet potato mixture to one half of each tortilla.
Top with some pepper jack cheese, then fold the tortillas in half and press firmly to seal. Sprinkle a little extra cheese on top.
Bake in the preheated oven for about 15 minutes, or until golden and the cheese is melted and bubbly.
While the tacos bake, make the chile lime crema. In a blender or food processor, combine the sour cream or Greek yogurt, lime zest and juice, chili powder, garlic powder, and a pinch of salt. Add a pinch of cayenne if you want some heat, then blend until smooth.
Once the tacos are crispy and golden, remove from the oven. Dress with pickled red onions, avocado, lime wedges, and a drizzle of the chile lime crema.