Season the chicken breasts with salt and pepper on both sides.
Heat olive oil in a skillet over medium heat.
Cook the chicken for 5–7 minutes per side until golden brown and cooked through (internal temperature of 165°F). Remove from the skillet and set aside.
In a bowl, whisk together soy sauce, brown sugar, rice vinegar, garlic, and ginger.
In a small cup, mix cornstarch with water to create a slurry.
Pour the soy sauce mixture into the skillet and bring it to a simmer.
Stir in the cornstarch slurry and cook for 2–3 minutes, stirring constantly, until the sauce thickens.
Return the chicken breasts to the skillet, spoon the sauce over them, and let them simmer for 2–3 minutes to absorb the flavors.
Plate the chicken and drizzle extra teriyaki sauce over the top. Serve with your choice of sides.