Slice the chicken breast into thick strips or even cutlets for uniform cooking.
Place the chicken in a bowl and pour the buttermilk over it, ensuring every piece is submerged, then marinate for 30 minutes.
In a separate shallow dish, whisk together the almond flour, arrowroot powder, smoked paprika, garlic powder, onion powder, sea salt, and black pepper.
Remove each piece of chicken from the buttermilk, letting the excess drip off, and dredge thoroughly in the flour mixture, pressing down to ensure a thick coating.
Preheat your air fryer to 375°F and lightly coat the basket with avocado oil spray.
Arrange the chicken in a single layer in the basket and spray the tops of the chicken with avocado oil.
Air fry for 12-15 minutes, flipping halfway through and spraying any dry flour spots, until the coating is crispy and the internal temperature reaches 165°F.
While the chicken cooks, steam the green beans until they are bright green and tender-crisp, then serve them alongside the hot chicken.