In a medium bowl, beat the egg whites, buttermilk, and hot sauce together until mixture begins to thicken
In a large, shallow bowl, add flour, breadcrumbs, and seasonings.
In a large pan or skillet, heat oil over medium high heat.
Cut chicken breasts in half, making them bun-size (if breasts are too thick, slice lengthwise as well).
Dip chicken breasts into the buttermilk mixture and then the flour mixture. Repeat until all of the chicken has been coated.
Place battered chicken pieces into the hot oil. Cook for 7-9 minutes on both sides making sure both sides are fried evenly, pieces are crispy and golden brown on both sides.
Once cooked, removed fried chicken from hot oil and place on paper towels to absorb any excess oil.
Assemble chicken sandwich with hamburger bun, lettuce, tomato, pickles, and any other desired toppings.