Cube chicken breasts into bite size pieces, trimming away any excess skin.
In a medium bowl, whisk together milk, pickle juice and egg.
Place cubed chicken into milk/egg mixture. Cover it and let it hang out in the refrigerator for about an hour (overnight is even better if time allows.)
When ready to cook, start preheating oil in your fryer or deep pot to 375F degrees.
In a gallon size Ziploc bag, combine flour, powdered sugar, cornstarch, salt & pepper.
Give it a good shake to combine ingredients.
Add in cubed chicken, small batches at a time, to the flour mixture.
Seal and shake until chicken is coated.
In small batches, place chicken into fryer.
Cook until golden brown. About 4-6 minutes. Internal temperature of chicken should be 165f degrees.
Remove and drain on paper towels. Continue with above steps until all your chicken is cooked.
Definitely try to use buttermilk here. It really tenderizes the chicken. If you have time, marinate the chicken in the buttermilk, egg and pickle juice mixture for as long as possible. But you can use regular milk if that is all you have.
You'll want to use dill pickle juice with this. The bread and butter pickle juice is just a bit too sweet.