Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized cubes and place them in a large mixing bowl.
Dice the red bell pepper and slice the zucchini into half-moons, then add them to the bowl with the chicken.
Drizzle the olive oil over the chicken and vegetables, then sprinkle with chili powder, smoked paprika, sea salt, black pepper, and garlic powder.
Toss everything thoroughly until the chicken and vegetables are evenly coated in the oil and spice mixture.
Spread the mixture in a single layer on the prepared baking sheet, ensuring there is space between pieces for roasting rather than steaming.
Roast in the oven for 18-20 minutes, or until the chicken is cooked through and the vegetables are tender with slightly browned edges.
Remove from the oven and transfer to a serving bowl, garnishing with freshly chopped cilantro before serving.