Preheat the oven to 400°F and spray a large 11 x 8-inch baking dish with non-stick cooking spray.
Make the sauce base: In a medium saucepan, whisk together the soy sauce, brown sugar, honey, vinegar, ground ginger, garlic, sesame oil, and water over medium heat. Bring to a simmer, then reduce the heat to low. Simmer for 3 to 4 minutes.
Thicken the sauce: Whisk together 3 tablespoons of cornstarch with 4 tablespoons of cold water. Slowly whisk the slurry into the simmering sauce. Continue to cook until the sauce has thickened, about 2 to 3 minutes. Remove from heat.
Prepare the chicken: Pat the chicken dry with paper towels and transfer it to your prepared baking dish in a single layer. Drizzle with olive oil and sprinkle both sides with salt and pepper, to season. Pour half of the prepared teriyaki sauce (approximately 1 cup) over the top of the chicken breasts. Reserve the remaining sauce for later. Use a fork or kitchen tongs to turn over the chicken several times to fully coat in your sauce.
Bake: Tent your baking dish with foil and transfer it to the oven. Bake, covered, for 20 minutes. Then uncover and continue to bake for an additional 5-15 minutes, or until the internal temperature registers 160°F as measured with a digital meat thermometer.
Rest and serve: Allow the chicken to rest for 5 minutes before slicing and serving with the remaining teriyaki sauce. Garnish with sliced green onions and sesame seeds, if desired.