Set out a large baking sheet lined with wax paper or parchment.
In a small bowl, mix mayonnaise, hot sauce and sweet chili sauce until smooth. Set aside. Serve chilled or at room temperature.
In a large bowl, mix flour, cornstarch, eggs, buttermilk, and buffalo hot sauce. Blend completely. If batter is too thick, thin with a splash of buttermilk.
Spread out Panko in a shallow dish. Working in batches, coat chicken pieces in batter, roll in Panko, and set on baking sheet until all pieces are coated
Heat oil in a large skillet over medium-high heat. Working in small batches, fry chicken pieces in oil for 5-6 minutes, until cooked thru and golden brown, turning over when one side is browned.
Drain chicken pieces on paper towel lined plate. Transfer to serving plate. Serve hot with dipping sauce.
** If frying in a skillet, heat approx 1-1/2 to 2 inches of oil in bottom of pan. Fry in hot oil for 2-3 minutes on each side, until cooked thru and golen brown.