Cut the chicken breast into cubes about an inch thick, dry with kitchen napkins, season with salt and pepper.
Place the chicken in a medium glass bowl and cover with half of the teriyaki sauce.
Bring the covered chicken to the refrigerator for about two hours while it is in the marinade.
In a large skillet place the oil, when it is hot add the chicken cubes one by one so that they are separated from each other. Let them brown on all sides.
Add the rest of the teriyaki sauce and turn off the kitchen. Let stand covered.
A few minutes before serving, sprinkle with sesame seeds and chopped scallions.