Whisk 1 tbsp of the Greek yogurt with the lemon juice, garlic powder, onion powder, sea salt, black pepper, and smoked paprika in a small bowl.
Coat the chicken breast thoroughly in the yogurt marinade and let it rest for 15 minutes to tenderize.
In a separate bowl, whisk the egg, the remaining 1 tbsp of Greek yogurt, 2 tbsp of the oat flour, and the baking powder until a smooth waffle batter forms.
Dredge the marinated chicken breast in the remaining 2 tbsp of oat flour until evenly coated on all sides.
Lightly brush the coated chicken with avocado oil and air-fry at 375°F for 12-15 minutes, turning halfway through, until the exterior is golden and the internal temperature reaches 165°F.
Pour the waffle batter into a preheated, lightly greased waffle iron and cook until the waffle is firm and steam stops rising.
Place the golden chicken atop the hot waffle and finish with a drizzle of maple syrup.