Reduce to medium, then flip the chicken and cook without stirring until browned on the second sides, 3 to 4 minutes. Add the garlic and ginger; cook, stirring, until fragrant, about 30 seconds.

Push the chicken to the perimeter of the pan. To the center, add the remaining 1 tablespoon oil, scallion whites and ginger; cook, stirring, until lightly browned, about 1½ minutes.