Heat the vegetable oil in a large pan over medium-high heat.
Add the sliced chicken breasts and cook until browned and cooked through, about 5-7 minutes.
Add the mixed vegetables to the pan and stir-fry for an additional 3-4 minutes until they are tender-crisp.
Pour in the stir-fry sauce and toss everything together, cooking for another 1-2 minutes to combine flavors fully.
Season with salt and pepper to taste, adjusting for your preference.
Serve hot over cooked rice for a complete meal.
