Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Dice the sweet potato into half-inch cubes and chop the chicken breast into uniform, bite-sized pieces.
In a large mixing bowl, whisk together the olive oil, lime juice, ground cumin, smoked paprika, sea salt, and black pepper.
Add the sweet potatoes, chicken, sliced red bell peppers, and red onion to the bowl, tossing thoroughly until everything is evenly coated in the spice mixture.
Spread the ingredients in a single layer across the prepared baking sheet, ensuring they aren't overcrowded to allow for proper browning.
Roast for 20 to 25 minutes, tossing the medley halfway through, until the chicken is cooked through and the sweet potatoes are tender and golden.
Remove from the oven and garnish with freshly chopped cilantro before serving warm.