Closely adapted from Christopher Kimball, Milk Street.
Toss the chicken with the soy sauce, 1 tablespoon of fish sauce and 1/2 teaspoon of ground white pepper. Let marinate for 15 minutes, then drain and pat the chicken pieces dry.
Stir together the vinegar and chopped basil.
Heat 1 tablespoon of the vegetable oil in a large nonstick skillet. Add the chicken pieces and cook until the chicken is browned and cooked through. Transfer to a clean bowl and then toss in the basil vinegar. Set aside.
Heat the remaining 2 tablespoons of oil. Add the garlic first, stirring continuously to prevent burning. When it darkens a bit, add the chipped white parts of the scallions. Cook for 2-3 minutes.
Add the sweet bell pepper and pea pods. Toss to mix into the garlic and scallion whites. Cook for about 3 minutes, continuing to stir.
Stir in the coconut syrup (or sugar). Add the chicken back into the pan, along with any accumulated juices. Add the scallion greens and remaining 2 tablespoons fish sauce and toss.
Turn off the heat and add the basil leaves and toss until the basil leaves are wilted (I reserved a few for garnishing for pictures). Taste for more ground white pepper.
Serve with Jasmine rice and chopped pickled Thai bird chile peppers for those who like their food hot.