Cut the chicken breasts into bite-sized pieces. Place the chicken in a large bowl and pour the buttermilk over the top. Stir to coat the chicken evenly. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes, or up to 8 hours.
In a shallow dish, combine the flour, chili powder, garlic powder, onion powder, paprika, salt, and black pepper.
Remove the chicken from the buttermilk and toss it in the flour mixture, making sure to coat each piece evenly.
Heat about 1 inch of vegetable oil in a large, deep skillet over medium-high heat. The oil is ready when a pinch of flour sizzles when it is added to the skillet.
Working in batches, carefully place the coated chicken pieces into the hot oil. Fry the chicken for 3-4 minutes on each side, or until golden brown and crispy. Use tongs or a slotted spoon to remove the chicken from the oil and transfer it to a paper towel-lined plate to drain.
Serve the spicy chicken bites hot, with your favorite dipping sauce on the side. Ranch dressing, blue cheese, or honey mustard all make great options!