Place the chicken breast between two sheets of parchment paper and pound with a meat mallet until it is an even half-inch thickness.
In a shallow bowl, soak the chicken in the buttermilk for at least 15 minutes to tenderize.
In a separate shallow dish, 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 seasoned flour mixture until fully 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 coating is golden brown and the internal temperature reaches 165°F.
While the chicken rests, lightly toast the whole wheat 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 topping with the dill pickle slices.