Place the chicken breast between parchment paper and pound to an even thickness for uniform cooking.
Submerge the chicken in buttermilk in a shallow bowl and let it marinate for at least 15 minutes in the refrigerator.
In a separate shallow 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 the excess drip off, then dredge thoroughly in the flour mixture until fully coated.
Lightly coat the chicken and the air fryer basket with avocado oil to ensure a golden finish.
Air fry at 375°F for 12-15 minutes, flipping halfway through, until the internal temperature reaches 165°F and the exterior is crispy.
Toast the whole grain bun in a dry pan or the air fryer for 1-2 minutes until golden brown.
Assemble the sandwich by layering the butter lettuce, crispy chicken, and dill pickles on the toasted bun.