Trim any fat from the chicken, then cut it into 2-inch chunks. Place the chicken in a large mixing bowl or a large storage bag.
In a small mixing bowl or measuring cup, whisk together ½ cup buttermilk, ½ teaspoon kosher salt, ½ teaspoon black pepper, and ½ teaspoon garlic powder. Pour this mixture over the chicken and toss to coat. Seal the bag or cover the bowl with plastic wrap, then refrigerate for at least 30 minutes or up to 12 hours.
Once the chicken has been marinated, preheat the oven to 425℉. Spray a baking sheet lined with a baking rack with nonstick spray and set it to the side.
In a shallow dish, whisk together ¼ cup all purpose flour, ½ cup panko bread crumbs, 1 teaspoon kosher salt, 1 teaspoon garlic powder, 1 teaspoon paprika, 1 teaspoon onion powder, and ½ teaspoon black pepper.
Remove the chicken from the buttermilk, shake off excess liquid, dip each piece into the flour mixture, toss to coat, shake off excess flour, and place the coated chicken on a baking rack on top of a baking sheet. Lightly spray the top of the breaded chicken with cooking spray.
Bake for 10-12 minutes, or until the chicken is browned and cooked to 165℉. There is no need to flip the chicken, as the heat will circulate around the baking rack, ensuring each side gets crispy.
After the chicken is baked, let cool slightly, then brush each side of the boneless wings with the buffalo sauce. Alternatively, you can gently toss the boneless wings with the sauce in a large bowl.
Serve immediately with dipping sauce of choice.
Notes
Chicken: I prefer boneless, skinless chicken breasts for firm, meaty bites similar to restaurant versions. Chicken tenders also work. If using thighs, expect a slightly richer, softer texture and cook until they reach 185℉.Homemade Buttermilk: Add ½ tablespoon lemon juice, apple cider vinegar, or white vinegar to a glass measuring cup. Add enough milk or non-dairy milk to make ½ cup total liquid, then let sit for 5-10 minutes before using. Use in place of buttermilk.Baking Sheet: Bake these boneless wings on a baking rack so heat circulates evenly and all parts of the chicken crisp up. Gluten-Free: Use a 1:1 Gluten-Free Flour Blend and gluten-free breadcrumbs.Other Sauces: Skip the Buffalo sauce and toss the baked chicken with BBQ sauce, honey mustard, sweet chili sauce, or your favorite wing sauce.Storage: Serve these boneless wings immediately to keep them crisp and crunchy. If you have leftover boneless wings, store them in an airtight container for up to 3 days. Reheat by placing them on a sheet pan and broiling for 2 minutes per side, or until warmed through. I don't recommend reheating using the microwave, as the breading will get soggy.