Start by dicing the chicken into bite-sized cubes, making it easy to cook and serve. Season the chicken lightly with salt and pepper for basic seasoning. Set the prepared chicken aside while you make the sauce.

In a small mixing bowl, whisk together 1/4 cup of soy sauce, 2 tablespoons of brown sugar, 1 minced garlic clove, 1 teaspoon of grated ginger, 1 tablespoon of rice vinegar, and 1 teaspoon of sesame oil. This combination creates a balanced sweet and savory flavor. Next, dissolve 1 tablespoon of cornstarch in 1/4 cup of water and stir it into the sauce mixture to help thicken the sauce later on.

Heat a non-stick skillet or wok over medium-high heat and add 1 tablespoon of cooking oil. Once the oil is hot, add the diced chicken pieces. Sear them for about 3-4 minutes on each side, cooking them until golden brown and fully cooked through. This step ensures the chicken gets a crispy exterior while staying juicy inside.

Once the chicken is cooked, pour the prepared teriyaki sauce into the skillet. Stir the chicken pieces in the sauce and cook for an additional 2-3 minutes, allowing the sauce to thicken and evenly coat the chicken. The sauce should become glossy and adhere to the chicken for a flavorful finish.

Remove the skillet from heat and garnish the teriyaki chicken with chopped green onions and sesame seeds. These toppings add a fresh and crunchy texture that complements the savory chicken. Serve and enjoy your homemade teriyaki chicken!