Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Slice the chicken breast into thin strips and chop the bell pepper, zucchini, and red onion into bite-sized pieces.
Place the chicken and vegetables onto the prepared baking sheet.
Drizzle with olive oil and sprinkle evenly with dried oregano, garlic powder, sea salt, and black pepper.
Toss everything together with your hands or tongs until well-coated, then spread into a single layer.
Roast in the oven for 18 to 20 minutes, or until the chicken is cooked through and the vegetables are tender and slightly charred.
While the chicken roasts, whisk together the Greek yogurt and lemon juice in a small bowl to create the sauce.
Warm the tortilla in a dry skillet over medium heat for about 30 seconds per side until pliable.
Spread the lemon-yogurt sauce down the center of the tortilla, top with the roasted chicken and vegetable mixture, fold in the ends, and roll tightly.