Place the chicken breast in a shallow bowl and pour the buttermilk over it, ensuring it is fully coated; let it marinate for at least 15 minutes.
In a separate small bowl, whisk together the almond flour, arrowroot powder, smoked paprika, garlic powder, onion powder, 0.25 tsp sea salt, and black pepper.
Preheat your air fryer to 375°F.
Remove the chicken from the buttermilk, letting excess drip off, then dredge it thoroughly in the flour mixture until evenly coated.
Lightly coat the air fryer basket with half of the avocado oil, place the chicken inside, and spray the top of the chicken with the remaining oil.
In a medium bowl, combine the oat flour, Greek yogurt, baking powder, and 0.125 tsp sea salt, stirring until a thick dough forms.
Shape the dough into a round biscuit and place it in the air fryer basket next to the chicken.
Air fry for 12-15 minutes, flipping the chicken halfway through, until the chicken is golden brown and the biscuit is firm and slightly toasted.
Let the chicken rest for 3 minutes before serving alongside the warm biscuit.