Place the chicken breast in a shallow bowl and pour the buttermilk over it, ensuring it is fully coated.
In a separate small bowl, whisk together the whole wheat flour, smoked paprika, garlic powder, onion powder, sea salt, and black pepper.
Remove the chicken from the buttermilk, letting any excess drip off, then dredge it thoroughly in the flour mixture until evenly coated.
Lightly brush or spray the coated chicken with olive oil on all sides to ensure a golden finish.
Place the chicken in the air fryer basket and cook at 400°F for 12 to 15 minutes, flipping halfway through, until the exterior is golden and crispy.
While the chicken cooks, lightly toast the whole grain bun in a dry pan or toaster until warm.
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.