Prep the chicken. Slice the chicken breasts against the grain into thin strips.
Pat dry with paper towels. Toss with a pinch of salt and black pepper. For extra tenderness, stir in 1 teaspoon cornstarch and 1 teaspoon soy sauce and let it sit while you prep the vegetables.
Prep the vegetables. Slice zucchini into half-moons about 1/4-inch thick.
Thinly slice the red bell pepper. Mince the garlic and ginger. Separate green onion whites from greens.
Make the sauce. In a small bowl, whisk soy sauce, rice vinegar, honey, sesame oil, chicken broth, and the remaining cornstarch until smooth.
Add red pepper flakes or sriracha to taste.
Heat the pan. Place a large skillet or wok over medium-high heat. Add 1 tablespoon of neutral oil and swirl to coat until shimmering.
Cook the chicken in batches. Add half the chicken in a single layer. Let it sear undisturbed for 1–2 minutes, then stir-fry until just cooked through, 3–4 minutes total.
Transfer to a plate. Repeat with remaining chicken, adding more oil if needed.
Stir-fry the aromatics. In the same pan, add a touch of oil if dry. Add green onion whites, garlic, and ginger.
Stir-fry for 30 seconds until fragrant. Don’t let the garlic burn.
Cook the vegetables. Add zucchini and bell pepper. Stir-fry for 3–4 minutes until the zucchini is bright and slightly tender but still crisp.
Season with a small pinch of salt and pepper.
Combine and sauce. Return the chicken and any juices to the pan. Whisk the sauce again (cornstarch settles) and pour it in. Toss to coat.
Cook 1–2 minutes until the sauce thickens and glazes the chicken and vegetables.
Taste and adjust. Add a splash of soy sauce for salt, a squeeze of honey for balance, or more heat if you like. Stir in green onion tops.
Serve. Top with toasted sesame seeds if you have them. Serve over steamed rice, quinoa, or cauliflower rice for a lower-carb option.