Pat the chicken thighs dry and season them with the chipotle powder, cumin, paprika, salt, and pepper to create a smoky, even seasoning.
Heat the olive oil in a large skillet over medium heat. Sear the seasoned chicken thighs until they’re golden on both sides, about 3–4 minutes per side. Remove and set aside.
In the same skillet, add the onion and a pinch more salt. Cook until the onion is translucent and slightly caramelized, about 3–4 minutes. Add the garlic and cook for another 30 seconds.
Add the diced sweet potatoes to the skillet and stir to coat them in the remaining oil and seasonings. Cook for 5–7 minutes, allowing the edges to get a bit color and the potatoes to begin softening.
Pour in the chicken broth to deglaze the pan, scraping up any browned bits from the bottom. Return the chicken thighs to the skillet, nestling them among the potatoes.
Reduce the heat to medium-low, cover the skillet, and simmer for 12–15 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the sweet potatoes are tender.
Uncover and let the sauce simmer for a few minutes to thicken slightly. Squeeze fresh lime juice over the top and sprinkle with chopped cilantro if using.
Taste and adjust the seasoning with a pinch more salt or lime, if desired. Serve hot, spooning extra sauce over the chicken and potatoes.