Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Slice the chicken breast into thin strips and thinly slice the bell peppers and red onion.
Place the chicken, peppers, and onions onto the sheet pan.
Drizzle the olive oil over the mixture and sprinkle evenly with chili powder, cumin, garlic powder, sea salt, and black pepper.
Toss everything together with your hands or tongs until the chicken and vegetables are well-coated in oil and spices, then spread them out in a single layer.
Roast in the oven for 18-20 minutes, or until the chicken is cooked through and the vegetables are tender and slightly charred at the edges.
While the chicken is roasting, warm the low carb tortillas in a dry skillet over medium heat for 30 seconds per side.
Remove the sheet pan from the oven, squeeze the fresh lime juice over the mixture, and garnish with chopped cilantro.
Divide the chicken and pepper mixture evenly between the two warm tortillas and serve immediately.