Prep the chicken and veggies: Slice the chicken thinly against the grain.
Cut all vegetables into bite-size pieces. Keep garlic and ginger separate so they don’t burn during the stir fry.
Make the sauce: In a bowl or measuring cup, whisk soy sauce, rice vinegar, oyster sauce, sesame oil, honey, red pepper flakes, broth, and cornstarch until smooth. Reserve 2 tablespoons of this mixture for a quick chicken marinade.
Marinate the chicken (quickly): Toss the sliced chicken with the reserved 2 tablespoons of sauce. Let it sit while you heat the pan and organize the vegetables.
Even 5 minutes helps.
Heat the pan: Place a large nonstick skillet or wok over medium-high heat. Add 2 teaspoons oil and swirl to coat. You want the pan hot so the chicken sears and the veggies stay crisp.
Cook the chicken: Add the chicken in a single layer.
Stir only as needed to cook through, about 4 to 5 minutes. Remove to a plate. Don’t crowd the pan; work in two batches if necessary.
Stir fry the veggies: Add the remaining 1 teaspoon oil to the pan.
Add onion, carrot, and broccoli. Cook 2 to 3 minutes, stirring frequently. Add bell pepper and snap peas; cook another 2 minutes until crisp-tender.
Add aromatics: Push the veggies to the sides.
Add garlic and ginger to the center and cook 20 to 30 seconds until fragrant, not browned.
Combine and sauce: Return the chicken and any juices to the pan. Whisk the sauce again (cornstarch settles), then pour it in. Stir constantly for 30 to 60 seconds as it thickens and lightly coats everything.
Taste and adjust: If you prefer more brightness, add a small splash of rice vinegar or a squeeze of lime.
For heat, add a pinch more red pepper flakes.
Serve: Top with green onions and sesame seeds. Spoon over cauliflower rice or a modest scoop of brown rice to keep calories in check.