Using a blender, food processor, or immersion blender, puree the orange juice, chipotles, garlic, salt, pepper, and oregano until smooth. In a large resealable plastic bag, combine the chicken and the marinade. Refrigerate for at least 30 minutes or overnight.
Preheat the broiler. Spray a rimmed baking sheet with cooking spray.
Lift the chicken out of the marinade, letting any excess drip off. Arrange the chicken on one half of the prepared baking sheet. Place the onions and peppers on the other side of the baking sheet, season with extra salt, and spray lightly with cooking spray. Broil until the chicken is cooked through and the vegetables are browned in spots, 5–7 minutes.
Meanwhile, heat a medium cast-iron skillet over medium-high heat. Add the tortillas, one at a time, and warm on both sides, about 10 seconds per side. Serve the chicken and vegetables wrapped in the tortillas. If you like, top with avocado and yogurt and place lime wedges on the side