In a large Ziploc bag or bowl, combine the flour, baking soda, onion powder, garlic powder, salt, and pepper.
In a shallow bowl, whisk together eggs and buttermilk.
Place Panko breadcrumbs in a separate shallow bowl.
Add the chicken pieces to the bag with the seasoned flour. Seal and toss to coat each piece in the seasoned flour.
Working in batches, dip the chicken pieces in the egg mixture and then dredge in the breadcrumbs. Let the chicken rest on a wire rack for a few minutes while you heat the oil.
In a large cast-iron skillet or Dutch oven, heat the oil to 350°F. Working in batches, fry chicken until deep golden brown, about 2-3 minutes total (flipping halfway through). Transfer to a paper towel-lined tray and sprinkle with a little more salt.
Keep the chicken nuggets warm in a 200°F oven while you finish frying the remaining pieces.
Video
Notes
I prefer to add the seasoning to the flour in order to season the chicken. Then, as soon as the nuggets come out of the oil, season them with a little bit more saltwhile they're still warm so that it adheres to the crispy coating.
Give the breaded chicken time to rest (dry) for a few minutes while the oil heats. This will help the breading adhere to the meat when it cooks.
Use either peanut oil or vegetable oil to fry the chicken nuggets. I typically use peanut oil because it's affordable, it has a high smoke point, and it will not flavor your meat.
I like to use a deep-fry thermometer to make sure that the oil reaches and stays at a consistent temperature of 350°F. If you don't have a thermometer, no problem! Instead, when the oil is hot (but not smoking), add a drop of water to the pan -- if it sizzles, the oil is hot enough for the chicken. You want to maintain a fairly steady temperature as the chicken cooks, so don't overcrowd the pan with too many pieces at once (which will bring down the temperature).
To ensure crispy chicken nuggets,keep the temperature of your oil at a steady 350°F. That's why you don't want to overcrowd the pan by trying to cook too many nuggets at once. If the oil is too cool, the chicken will absorb the oil and have a soggy texture when done.
Never cover your warm fried chicken nuggets with foil. This traps steam and moisture, which will make the nuggets soggy.