Slice the sweet onion into thick rings and cut the chicken breast into thin, even strips.
In a medium bowl, whisk together the chickpea flour, light beer, egg white, and half of the garlic powder, smoked paprika, salt, and pepper until a smooth batter forms.
Dip each onion ring and chicken strip into the batter, ensuring they are fully coated, and allow any excess to drip off.
Lightly grease the air fryer basket with avocado oil and arrange the battered pieces in a single layer, working in batches if necessary.
Air fry at 375°F for 12-15 minutes, flipping halfway through, until the coating is deeply golden and crispy.
While frying, prepare the dipping sauce by mixing the Greek yogurt with lemon juice and the remaining spices in a small ramekin.
Serve the hot onion rings and chicken immediately with the chilled yogurt dip.