Prep the chicken: In a bowl, toss sliced chicken with 1 tablespoon soy sauce and 1 tablespoon cornstarch. Let it sit while you prep the veggies, about 10 minutes.
Whisk the sauce: In a small bowl, mix soy sauce, oyster sauce, honey, rice vinegar, sesame oil, red pepper flakes, chicken broth, and 2 teaspoons cornstarch.
Set aside.
Heat the pan: Place a large skillet or wok over medium-high heat. Add 1 tablespoon oil and let it get hot until shimmering.
Sear the chicken: Cook chicken in a single layer (work in batches if needed) for 3–4 minutes, stirring once or twice, until lightly browned and just cooked through. Transfer to a plate.
Stir-fry the veggies: Add remaining 1 tablespoon oil.
Toss in onion, carrot, and broccoli. Stir-fry 2–3 minutes until starting to soften.
Add quick-cook veggies: Add bell pepper and snow peas. Stir-fry another 2 minutes until crisp-tender.
Add aromatics: Push veggies to the sides.
Add garlic and ginger to the center. Stir 20–30 seconds until fragrant.
Combine and sauce: Return chicken and any juices to the pan. Give the sauce a quick stir, then pour it in.
Toss everything for 1–2 minutes until the sauce thickens and coats.
Finish: Taste and adjust with a splash of soy sauce or a pinch of honey. Sprinkle green onions and sesame seeds.
Serve: Spoon over rice, quinoa, or cauliflower rice. Enjoy hot.