Place the chicken breast between two sheets of parchment paper and pound to an even thickness, then slice into wide strips.
Submerge the chicken strips in the buttermilk in a shallow bowl and let marinate for at least 15 minutes.
In a separate shallow dish, whisk together 2 tablespoons of arrowroot powder, almond flour, garlic powder, onion powder, paprika, sea salt, and black pepper.
Dredge each piece of chicken in the flour mixture, pressing firmly to ensure a thick, even coating.
Heat the avocado oil in a large skillet over medium heat. Once hot, add the chicken and cook for 4-5 minutes per side until golden brown and cooked through.
Remove the chicken from the pan and set aside on a plate.
In the same skillet, whisk the almond milk, nutritional yeast, and the remaining 1 teaspoon of arrowroot powder into the pan drippings.
Simmer the sauce over medium-low heat for 2-3 minutes, whisking constantly until the gravy thickens into a smooth consistency.
Serve the crispy chicken immediately topped with the warm gravy.