In a large bowl, combine flour, salt, and pepper. Dredge the chicken pieces in the flour mixture, shaking off any excess. Dip the floured chicken into the beaten egg, allowing any excess to drip off.
In a large skillet or wok, heat the vegetable oil over medium-high heat. Add the chicken pieces in batches, frying until golden brown and cooked through, about 5-7 minutes. Remove the chicken and drain on paper towels.
In the same skillet, add the chopped bell peppers and onion. Sauté for about 3-4 minutes until they begin to soften. Add the pineapple chunks and cook for an additional 2 minutes.
In a separate bowl, whisk together the sugar, apple cider vinegar, ketchup, soy sauce, garlic powder, and ginger powder. Pour the sauce over the sautéed vegetables and bring to a simmer. Stir in the cornstarch mixture and cook until the sauce thickens, about 1-2 minutes.
Add the fried chicken back into the skillet, tossing to coat the chicken evenly with the sauce. Cook for another minute to heat through.
Serve immediately over steamed rice or noodles.