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, allowing it to marinate for at least 15 minutes in the refrigerator.
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, then dredge in the flour mixture, pressing firmly to ensure a thick, even coating.
Preheat your air fryer to 400°F (200°C).
Lightly spray or brush the breaded chicken with avocado oil and place in the air fryer basket in a single layer without crowding.
Air fry for 12-15 minutes, flipping halfway through, until the exterior is golden brown and the internal temperature reaches 165°F.
While the chicken is air frying, steam the green beans in a steamer basket or microwave with a splash of water until they are tender-crisp.
Serve the crispy chicken immediately alongside the steamed green beans for a balanced, high-protein feast.