Prep your ingredients: Slice the chicken thinly against the grain. Core and shred the cabbage. Slice the onion and bell pepper.
Mince garlic and ginger. Have everything ready before you heat the pan.
Season the chicken: In a bowl, toss the chicken with 1 tablespoon soy sauce, a pinch of salt, and black pepper. Let it sit while the pan heats.
Heat the skillet: Set a large wok or wide skillet over medium-high heat.
Add 1 tablespoon oil and swirl to coat.
Sear the chicken: Add the chicken in an even layer. Cook 4–6 minutes, stirring occasionally, until browned and cooked through. Transfer to a plate and keep warm.
Sauté aromatics: Add the remaining 1 tablespoon oil to the pan.
Toss in the onion, garlic, and ginger. Stir 30–60 seconds until fragrant, being careful not to burn the garlic.
Add cabbage and pepper: Add the cabbage and bell pepper. Sprinkle with a pinch of salt.
Stir-fry 4–6 minutes until the cabbage softens but still has bite. If the pan looks dry, add a splash of water to create steam.
Make the sauce: In a small bowl, combine remaining soy sauce, rice vinegar, sesame oil, and chili garlic sauce if using.
Combine: Return the chicken and any juices to the pan. Pour in the sauce.
Toss everything for 1–2 minutes until glossy and well coated.
Taste and adjust: Add more salt, pepper, or soy sauce as needed. For extra heat, add more chili sauce. For brightness, splash in a bit more vinegar.
Finish and serve: Remove from heat.
Top with sesame seeds and green onions. Serve hot as-is or with a small side of cauliflower rice if you want a bigger plate without extra carbs.