olive oil (plus more if needed) • medium onions, halved and thinly sliced • garlic, peeled and smashed • sweet potato peeled and diced (optional) • roughly chopped cilantro (more for garnish) • scallions diced (more for garnish) • limes, 1 halved, 1 into wedges for serving • cumin • dried oregano • salt (more to taste once chicken shredded) • pepper (more to taste once chicken shredded) • whole chicken, frozen is ok in a pinch •