Place the chicken breast between two sheets of parchment paper and pound with a meat mallet until it reaches an even half-inch thickness.
In a shallow bowl, submerge the chicken in buttermilk and let it marinate in the refrigerator for at least 30 minutes.
In another shallow dish, whisk together the whole wheat flour, smoked paprika, garlic powder, sea salt, and black pepper.
Remove the chicken from the buttermilk, allowing excess to drip off, then dredge thoroughly in the flour mixture until fully coated.
Lightly coat the chicken with avocado oil using a brush or spray, then place it in the air fryer basket.
Air fry at 375°F for 12-15 minutes, flipping halfway through, until the exterior is golden brown and the internal temperature reaches 165°F.
While the chicken rests, lightly toast the sprouted grain bun in a dry pan over medium heat.
Assemble the sandwich by placing the butter lettuce on the bottom bun, followed by the crispy chicken and dill pickles, then top with the remaining bun half.