Begin by cutting the chicken thighs into bite-sized pieces.

In a bowl, combine soy sauce, mirin, brown sugar, sesame oil, minced garlic, and grated ginger.

Add the chicken pieces to the marinade, ensuring they are well coated. Let them sit for at least 10 minutes.

Place your skillet over medium-high heat and add a drizzle of sesame oil.

Add the marinated chicken to the hot skillet, spreading it out in a single layer. Cook until browned and cooked through, about 8-10 minutes.

Once the chicken is cooked through, pour in the reserved marinade. Stir in the cornstarch slurry and cook for another 2-3 minutes until the sauce thickens.

Remove from heat and garnish with sliced green onions and sesame seeds.

Serve the teriyaki chicken over rice or alongside steamed vegetables.