Place the chicken breast between two sheets of parchment paper and pound with a meat mallet until it reaches a uniform half-inch thickness.
Submerge the chicken in a bowl with the buttermilk and let it marinate for at least 15 minutes to tenderize the meat.
In a 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 excess drip off, and dredge thoroughly in the flour mixture, pressing down to ensure a thick coating.
Heat the avocado oil in a large non-stick skillet over medium-high heat until shimmering.
Carefully place the chicken in the skillet and cook for 4 to 5 minutes per side until the exterior is golden brown and the internal temperature reaches 165 degrees Fahrenheit.
While the chicken rests, place the bun halves cut-side down in the skillet for 30 seconds until toasted and warm.
Assemble the sandwich by placing the lettuce and tomato on the bottom bun, followed by the crispy chicken and pickle chips, then top with the remaining bun.