Place the chicken breast between parchment paper and pound to an even thickness.
Submerge the chicken in buttermilk and marinate for at least 30 minutes in the refrigerator.
In a shallow bowl, whisk together almond flour, garlic powder, onion powder, sea salt, black pepper, and paprika.
Dredge the marinated chicken in the flour mixture, pressing firmly to ensure a thick, even coating.
Lightly coat the chicken with avocado oil and air-fry at 375°F for 12-15 minutes until the exterior is crunchy and golden.
While chicken cooks, mix Greek yogurt and Dijon mustard in a small bowl to create a zesty spread.
Toast the whole wheat bun until lightly browned.
Assemble the sandwich by spreading the sauce on the bun, then layering the lettuce, tomato, pickles, and crispy chicken.