Begin by heating a grill pan or skillet over medium-high heat. Add about 2 teaspoons of vegetable oil to coat the surface or lightly brush the grill grates.

Season the chicken breasts on both sides with a generous pinch of salt and freshly ground pepper. Place them onto the heated surface and cook for approximately 4–5 minutes per side, or until the internal temperature reaches 165°F and the exterior is golden and lightly charred. Remove the chicken and cover it loosely with foil to retain warmth and moisture.

Drizzle the remaining teaspoon of oil into the pan or brush it over the grill again. Toss in the mixed vegetables and sauté or grill them for 4 to 5 minutes, stirring occasionally, until they are tender-crisp with slightly charred edges. Season the vegetables lightly with salt and pepper for enhanced flavor.

In a small saucepan set over medium heat, combine the soy sauce, water, brown sugar, honey, minced garlic, grated ginger, and toasted sesame oil. Stir the mixture well and bring it to a gentle simmer, allowing the sugar to dissolve and the flavors to meld.

In a separate bowl, whisk the cornstarch with 2 tablespoons of cold water until fully dissolved. Slowly pour this slurry into the simmering sauce, stirring continuously. Let the sauce boil for 1 minute, or until it thickens to a glossy consistency that coats the back of a spoon.

Slice the cooked chicken into bite-sized cubes or strips. Pour the warm teriyaki sauce over the chicken and gently toss to coat each piece evenly.

Distribute the cooked rice evenly into four serving bowls. Arrange the glazed chicken and sautéed vegetables neatly on top of the rice. Sprinkle with sesame seeds for a nutty finish and serve immediately while everything is hot and fresh.