Step 1: In a small bowl, whisk together the soy sauce, oyster sauce, sesame oil, and garlic powder. Set aside.
Step 2: Heat 1 tablespoon of vegetable oil in a large wok or skillet over high heat until shimmering.
Step 3: Add the diced chicken to the wok. Season with black pepper and stir-fry for 4-5 minutes until golden brown and cooked through. Remove chicken and set aside.
Step 4: Add the remaining tablespoon of oil to the wok. Pour in the beaten eggs and scramble quickly until just set. Push the eggs to one side of the pan.
Step 5: Add the white parts of the green onions and the peas and carrots to the empty side of the pan. Stir-fry for 1-2 minutes until fragrant.
Step 6: Add the cold rice to the pan. Use a spatula to break up any large clumps and toss it with the vegetables and eggs.
Step 7: Return the cooked chicken to the pan and pour the sauce mixture over the rice. Toss continuously for 2-3 minutes over high heat until the rice is evenly coated and heated through.
Step 8: Garnish with the green parts of the sliced onions and serve immediately.