Preheat your air fryer to 375°F (190°C).
In a large bowl, combine the halved Brussels sprouts, olive oil, garlic powder, onion powder, smoked paprika, salt, and pepper. Toss until the Brussels sprouts are evenly coated.
Place the seasoned Brussels sprouts in the air fryer basket in a single layer. You may need to do this in batches depending on the size of your air fryer.
Cook for 15-18 minutes, shaking the basket halfway through to ensure even cooking, until the Brussels sprouts are crispy and golden brown.
If desired, drizzle with balsamic vinegar and sprinkle with grated Parmesan cheese before serving.