Preheat your oven to 425°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Dice the chicken breast and potato into uniform 1/2-inch cubes to ensure they cook at the same rate and get maximum surface area for crisping.
In a large mixing bowl, whisk together the olive oil, chili powder, cumin, sea salt, and black pepper until well combined.
Add the diced chicken, potatoes, sliced bell peppers, and red onion to the bowl, tossing thoroughly until every piece is evenly coated in the spice oil.
Spread the mixture onto the prepared baking sheet in a single layer, making sure not to overcrowd the pan so the ingredients roast rather than steam.
Place in the oven and roast for 20 to 25 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the potatoes are golden and crispy.
Remove from the oven, drizzle immediately with fresh lime juice, and garnish with chopped cilantro before serving warm.