Tender chicken breast pieces are wok-tossed with roasted cashews, bell peppers, and a savory brown sauce. High in protein and quick to prepare, this dish works beautifully for clean eats meal prep or a satisfying family dinner.
Cut chicken breast into 1-inch pieces and toss with 1 teaspoon cornstarch and black pepper; set aside while preparing vegetables.
Slice bell peppers and onion into bite-sized pieces, mince garlic and ginger, and chop scallions into 1-inch segments.
In a small bowl, whisk together soy sauce, oyster sauce, rice vinegar, brown sugar, remaining cornstarch, and water to make the sauce; ensure cornstarch is fully dissolved.
Heat 1 tablespoon vegetable oil in a wok or large skillet over medium-high heat until shimmering. Add chicken; stir-fry for 3–4 minutes until golden but not overcooked, then transfer to a plate.
Add remaining oil, then stir-fry garlic, ginger, onions, and both bell peppers for 2 minutes over high heat, keeping vegetables crisp-tender.
Return chicken to the wok, add sauce, and toss everything quickly for 1–2 minutes until the sauce thickens and coats, chicken is just cooked through, and everything is well combined.
Add cashews and most of the scallions, stir just to incorporate, and immediately remove from heat to preserve crunch and texture.
Garnish with remaining scallions and serve hot.