Slice the chicken breast into thick, even strips.
Place the chicken in a bowl with the buttermilk and marinate for at least 20 minutes.
In a shallow dish, whisk together the arrowroot starch, almond flour, garlic powder, onion powder, smoked paprika, sea salt, and black pepper.
Remove each chicken strip from the buttermilk, letting the excess drip off, and dredge thoroughly in the flour and spice mixture until well coated.
Lightly coat the air fryer basket with avocado oil and place the chicken inside in a single layer.
Air fry at 400 degrees for 12 to 15 minutes, flipping halfway through, until the coating is golden and the chicken is cooked through.
In a small saucepan, whisk the almond milk, nutritional yeast, and a tiny pinch of arrowroot over medium heat until the mixture thickens into a smooth gravy.
Serve the crispy chicken immediately drizzled with the warm, creamy gravy.