Velvet the chicken: In a bowl, toss the chicken pieces with 1 tablespoon of the soy sauce and 1 tablespoon of the cornstarch until the coating turns into a thin, even paste with no dry spots. Let it sit for at least 10 minutes while you prep everything else.

Whisk the sauce: In a measuring cup, whisk the remaining 3 tablespoons soy sauce with the remaining 1 tablespoon cornstarch until smooth, then whisk in the oyster sauce, hoisin, rice vinegar, sesame oil, brown sugar, white pepper, and chicken broth. Set it right next to the stove.

Sear the chicken: Heat 1 tablespoon of the vegetable oil in a large skillet or wok over high heat until it shimmers. Add the chicken in a single layer and let it sit undisturbed for 2 minutes to brown, then stir and cook 2 to 3 minutes more, until the pieces are golden and reach 165°F. Move the chicken to a plate.

Stir fry the vegetables: Add the remaining 1 tablespoon oil to the hot pan along with the onion and bell pepper. Cook for 2 to 3 minutes, stirring often, until they're charred in spots but still have snap. Add the garlic and ginger and stir for 30 seconds, just until fragrant.

Add the sauce: Whisk the sauce again to redistribute the cornstarch, then pour it into the pan. Bring it to a bubble and stir for 1 to 2 minutes, until it turns glossy and thick enough to coat the back of a spoon.

Return the chicken: Add the chicken and any juices from the plate back to the pan and toss for about 1 minute, until everything is coated and hot.

Finish with cashews: Take the pan off the heat and stir in the cashews and most of the green onions. Serve right away over the cooked white rice, with the last of the green onions scattered on top.