Cut the chicken breast or thighs into 1-inch bite-sized cubes and set aside on a plate. In a shallow bowl, whisk together the flour, cornstarch, garlic powder, chili powder, salt, and pepper—this dry coating base is key to creating a crispy exterior. In another bowl, whisk together the egg and milk until well combined to create your wet batter. I like to use a shallow dish for the wet mixture because it makes dipping the chicken much easier and faster.
Pour the vegetable oil into a large skillet or shallow pan and heat over medium-high heat until it reaches approximately 350°F (or until a small piece of chicken coating sizzles immediately when dropped in). Let the oil heat for 2-3 minutes while you prepare your chicken—proper oil temperature is essential for achieving a golden, crispy exterior without the chicken absorbing excess oil.
Working in batches to avoid overcrowding the pan, dip each chicken cube into the egg and milk mixture from Step 1, then immediately coat thoroughly in the dry mixture. Place the coated chicken into the hot oil and fry for 3-4 minutes, stirring occasionally, until golden brown on all sides. Avoid crowding the pan—frying in 2-3 batches ensures even cooking and maintains the oil temperature. I find that working with about 8-10 pieces per batch keeps the oil hot enough for a proper crispy crust.
Using a slotted spoon or spider strainer, transfer the fried chicken bites to a paper towel-lined plate to drain excess oil. Once all batches are complete, arrange the chicken on a serving plate. In a small bowl, whisk together the sweet chili sauce and fresh lime juice until well combined, then pour generously over the warm chicken bites. Top with the finely chopped fresh chives and serve immediately while still warm and crispy.