Heat 1 tablespoon of oil in a large skillet until shimmering. Add the chicken, season with salt and soy sauce, and cook until golden and cooked through. Transfer to a bowl.
Add another tablespoon of oil to the pan. Cook the onion and garlic until softened and lightly golden.
Add the mixed veggies and sauté until they brighten and soften.
Push the veggies on the side and scramble the eggs on the empty side of the pan.
Add the cold rice. Break up clumps and spread it out so it crisps.
Add soy sauce and sesame oil. Stir and cook until the rice is evenly coated and warmed through.
Fold the scrambled eggs into the rice. Add the chicken back in and stir everything together.
Taste and adjust seasoning. Serve hot.