Place the chicken breast between two sheets of parchment paper and pound to an even half-inch thickness.
Place the chicken in a shallow bowl and pour the buttermilk over it, ensuring it is fully coated; let marinate for 15 minutes.
In a separate small bowl, whisk together the almond flour, arrowroot powder, smoked paprika, garlic powder, sea salt, and black pepper.
Remove the chicken from the buttermilk, letting the excess drip off, then dredge thoroughly in the flour mixture until well-coated.
Heat the avocado oil in a non-stick skillet over medium-high heat.
Add the chicken to the skillet and cook for 4-5 minutes per side until the exterior is golden-brown and the internal temperature reaches 165 degrees Fahrenheit.
Lightly toast the sprouted grain bun in the same skillet or a toaster.
Assemble the sandwich by placing the lettuce on the bottom bun, followed by the crispy chicken and dill pickles, then top with the remaining bun half.