Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Add the diced chicken and season with salt and pepper. Cook until the chicken is browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.

In the same skillet, add the remaining tablespoon of vegetable oil. Add the frozen peas and carrots and sauté for about 2-3 minutes until heated through. Push the vegetables to one side of the skillet.

Pour the beaten eggs into the empty side of the skillet and scramble until fully cooked. Mix the eggs with the vegetables.

Add the cooked rice to the skillet, breaking up any clumps. Stir in the cooked chicken, soy sauce, oyster sauce (if using), and sesame oil. Mix everything together and cook for an additional 3-5 minutes, allowing the rice to get slightly crispy.

Stir in the chopped green onions and adjust seasoning with more salt and pepper if needed. Remove from heat and serve hot.