Preheat the oven to 400°F and line a large baking sheet with parchment paper.
Arrange the chicken, onion, and peppers in a single layer on the prepared baking sheet.
In a medium bowl, whisk together the olive oil, chili powder, cumin, salt, paprika, sugar, garlic powder, and onion powder.
Drizzle the seasoning mixture over the chicken and vegetables, then toss to coat evenly.
Bake for 10 minutes, then stir everything on the pan.
Return to the oven and bake for another 5 minutes, or until the chicken is nearly cooked through.
Turn the oven to broil and cook for 2-3 minutes, until the edges are slightly charred and the chicken reaches an internal temperature of 165°F.
Serve in warm tortillas with your favorite toppings.