Place the chicken breast between two sheets of parchment paper and pound to an even half-inch thickness.
Place the chicken in a bowl and pour the buttermilk over it, allowing it to marinate for at least 20 minutes.
In a shallow dish, whisk together the arrowroot powder, almond flour, garlic powder, onion powder, sea salt, and black pepper.
Remove the chicken from the buttermilk and dredge it through the flour mixture, pressing firmly to ensure an even coating.
Heat the avocado oil in a large skillet over medium heat and fry the chicken for 5 to 6 minutes per side until golden brown and cooked through.
Remove the chicken from the pan and set it aside to rest.
In the same skillet, whisk the almond milk and a pinch of arrowroot into the remaining pan drippings over low heat until the gravy thickens.
Steam the green beans until tender-crisp, then serve the chicken topped with the warm gravy and fresh thyme.