Prep everything first. Slice the chicken thinly against the grain. Cut all vegetables into bite-size pieces.
Mince garlic and grate ginger. Stir-fries move fast, so have it all ready.
Make the sauce. In a small bowl, whisk soy sauce, rice vinegar, honey, oyster sauce (if using), sesame oil, red pepper flakes or sriracha, broth, and cornstarch until smooth. Set aside.
Heat the pan. Place a large skillet or wok over medium-high heat.
Add 1 tablespoon oil and swirl to coat.
Sear the chicken. Add the chicken in a single layer. Season lightly with salt and pepper. Cook 3–4 minutes, stirring occasionally, until just cooked through with some caramelized edges.
Transfer to a plate.
Cook the sturdy veggies. If the pan looks dry, add a little more oil. Add broccoli and carrots. Stir-fry 2–3 minutes until they start to soften but remain bright.
Add quick-cooking veggies. Add bell pepper, onion, and snap peas.
Stir-fry 2–3 minutes more. You want crisp-tender, not mushy.
Add aromatics. Push veggies to the sides. Add garlic and ginger to the center with a small splash of oil if needed.
Stir 30 seconds until fragrant, then toss with the vegetables.
Combine and sauce. Return chicken to the pan. Give the sauce a quick stir (cornstarch settles), then pour it in. Toss everything for 1–2 minutes until the sauce thickens and coats the stir fry.
Taste and adjust. Add a splash more soy for salt, vinegar for brightness, or chili for heat.
Remove from heat.
Serve. Spoon over rice, quinoa, or cauliflower rice. Top with green onions and sesame seeds.