Heat vegetable oil in a large pan over medium-high heat.
Add chicken strips and cook until golden brown. Remove and set aside.
In the same pan, add garlic and ginger, sautéing until fragrant.
Add bell pepper, carrot, and broccoli, stir-frying for 3-4 minutes.
Return the chicken to the pan and pour in soy sauce, oyster sauce, and sesame oil.
Stir in the cornstarch mixture and cook until the sauce thickens.
Season with salt and pepper, then serve over cooked rice.