Preheat the oven to 400F. Line a baking sheet with parchment paper.
Toss the sweet potato cubes with olive oil, chili powder, cumin, smoked paprika, salt, and pepper.
Spread the seasoned sweet potatoes on the prepared baking sheet and bake for 20-25 minutes or until golden brown and tender.
While the sweet potatoes are roasting, prepare the pickled onions. In a small bowl, whisk together the apple cider vinegar, sugar, and salt until the sugar has dissolved. Add the sliced red onion and toss to coat. Let sit for at least 10 minutes.
Heat the black beans in a small saucepan over low heat.
Warm the tortillas in a dry skillet or on a griddle.
To assemble the tacos, spoon some black beans onto each tortilla, followed by a generous helping of roasted sweet potatoes. Top with pickled onions, avocado slices, cilantro, and a squeeze of lime juice.
Serve immediately and enjoy!
