Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat.
Add the diced chicken and cook until golden brown and fully cooked, about 6 to 8 minutes.
Transfer the chicken to a plate and set aside.
Add the remaining tablespoon of oil to the skillet.
Pour in the beaten eggs and scramble until just cooked.
Push the eggs to one side of the pan.
Add the peas and carrots and cook for 2 minutes.
Add the chilled rice and break up any clumps with a spatula.
Return the cooked chicken to the skillet.
Stir in the soy sauce, sesame oil, garlic powder, and black pepper.
Cook for 3 to 4 minutes, stirring frequently, until everything is heated through.
Add the green onions and toss to combine.
Serve immediately.