Slice the chicken breast into even strips or nuggets.
In a shallow bowl, whisk together the buttermilk, sea salt, and black pepper.
Submerge the chicken pieces in the buttermilk mixture and let marinate for at least 20 minutes in the refrigerator.
In a separate shallow dish, combine the almond flour, arrowroot starch, smoked paprika, garlic powder, and onion powder.
Remove each piece of chicken from the buttermilk, allowing excess to drip off, then dredge thoroughly in the flour mixture, pressing firmly to ensure a thick coating.
Preheat your air fryer to 400°F and lightly coat the basket with the avocado oil.
Arrange the chicken in a single layer in the air fryer basket, ensuring they are not touching.
Air fry for 12-15 minutes, flipping halfway through, until the coating is golden brown and the chicken is cooked through.
While the chicken cooks, steam the green beans for 5-7 minutes until tender-crisp.
Serve the crispy chicken immediately alongside the hot green beans.