Preheat your oven to 400°F (200°C) and line a baking tray with parchment paper.
Prepare the chicken by placing it between two sheets of plastic wrap. Use a meat mallet or rolling pin to gently pound the chicken to an even thickness, about 1 inch.
In a large mixing bowl, combine flour, salt, pepper, and garlic powder. In another bowl, beat the egg. Place the panko breadcrumbs in a third bowl.
Coat each piece of chicken first in the flour mixture, then dip it into the beaten egg, and finally coat it with panko breadcrumbs. Make sure each piece is well covered.
Heat a few tablespoons of oil in a frying pan over medium-high heat. Once hot, add the chicken pieces and fry for about 3-4 minutes on each side until they are golden brown and cooked through. Alternatively, you can bake the chicken in the oven for about 20 minutes, flipping halfway through.
While the chicken is cooking, prepare the Bang Bang sauce by whisking together the mayonnaise, sweet chili sauce, sriracha, and lime juice in a mixing bowl.
Once the chicken is cooked, remove it from the pan and let it rest for a couple of minutes. Then, slice the chicken into strips and toss with the Bang Bang sauce until well coated.
Serve the Bang Bang Chicken on a platter, garnished with sliced green onions. Enjoy with rice or noodles if desired.