Pound the chicken breast to an even thickness and marinate in buttermilk for at least 30 minutes in the refrigerator.
In a shallow bowl, whisk together the almond flour, smoked paprika, garlic powder, sea salt, and black pepper.
Remove the chicken from the buttermilk and dredge it in the flour mixture, pressing firmly to create a thick, even coating.
Lightly spray the coated chicken with avocado oil and place it in the air fryer basket.
Air-fry at 375°F for 12-15 minutes, flipping halfway through, until the exterior is golden and the internal temperature reaches 165°F.
While the chicken cooks, toast the sprouted grain bun until the edges are slightly crunchy.
In a small bowl, mix the plain Greek yogurt and Dijon mustard to create a creamy, high-protein sandwich spread.
Assemble the sandwich by spreading the yogurt-mustard sauce on the bun, adding the crispy chicken, and topping with the dill pickles.