First prepare the sauce by adding the sugar, vinegar, coconut aminos, chicken stock, and ketchup to a medium saucepan. Stir and bring to a boil. Reduce to a low heat and leave until later.

Add chicken pieces and beaten egg to a large ziplock bag. Seal and shake to coat chicken. Then add the arrowroot starch to the bag, shaking again to lightly coat all the chicken pieces.

Add oil to a large nonstick skillet. Add the coated chicken. Fry over medium heat, a couple of minutes on each side until the coating begins to crisp. Add pepper and pineapple chunks. Continue to sauté over medium heat until chicken is browned and cooked through.

Add the sauce to chicken and peppers. Cover and reduce the heat down to a simmer and allow the juices to soak into the chicken for a few minutes. Top with sliced green onions.