In a bowl, combine the flour, salt, black pepper, garlic powder, and onion powder.

Dredge the chicken pieces in the flour mixture, ensuring they are evenly coated.

In a large skillet or wok, heat the vegetable oil over medium-high heat.

Add the coated chicken pieces to the skillet in a single layer. Fry for about 5-7 minutes, turning occasionally, until golden brown and cooked through. Remove the chicken from the skillet and drain on paper towels.

In a small bowl, mix together the orange marmalade, soy sauce, rice vinegar, cornstarch, water, sesame oil, and red pepper flakes (if using).

In the same skillet, pour the sauce mixture and bring it to a simmer over medium heat. Stir continuously until the sauce thickens, about 2-3 minutes.

Return the fried chicken to the skillet and toss it in the sauce until well coated.

Serve the orange chicken hot, garnished with sliced green onions and sesame seeds.