Preheat your oven to 425°F and line a large baking sheet with parchment paper.
Dice the Russet potatoes, bell peppers, and red onion into uniform half-inch cubes for even roasting.
In a large bowl, toss the vegetables with half of the olive oil, half of the chili powder, half of the cumin, and a pinch of salt and pepper.
Spread the vegetables in a single layer on the baking sheet and roast for 25 minutes until the potatoes are golden and tender.
While the vegetables roast, season the chicken breast on both sides with the remaining chili powder, cumin, garlic powder, salt, and pepper.
Heat the remaining olive oil in a large skillet over medium-high heat and sear the chicken for 6-7 minutes per side until fully cooked.
Let the chicken rest for 3 minutes before slicing into strips.
Serve the warm chicken alongside the roasted potatoes and peppers, garnished with fresh cilantro and a bright squeeze of lime juice.