Place the chicken breast between two sheets of parchment paper and pound with a meat mallet to an even half-inch thickness.
In a shallow bowl, submerge the chicken in the buttermilk and let it marinate for at least 10 minutes.
In a separate shallow dish, whisk together the whole wheat flour, garlic powder, onion powder, smoked paprika, sea salt, and black pepper until well combined.
Remove the chicken from the buttermilk, allowing the excess to drip off, then dredge it thoroughly in the seasoned flour mixture, pressing to adhere.
Heat the avocado oil in a cast-iron skillet over medium-high heat until shimmering.
Carefully place the chicken in the skillet and cook for 5 to 6 minutes per side until the crust is golden brown and the internal temperature reaches 165 degrees Fahrenheit.
While the chicken cooks, warm the whole grain biscuit in a toaster oven or conventional oven until heated through.
Transfer the crispy chicken to a plate lined with a paper towel to rest for 2 minutes before serving with the warm biscuit.