1. Prepare the Chicken: In a medium bowl, combine the cut chicken pieces with 1 tablespoon of soy sauce and 1 teaspoon of cornstarch. Toss well to coat the chicken evenly. This step helps to tenderize the chicken and gives it a slight crispness when cooked. Set aside while you prepare the vegetables.

2. Whisk the Stir Fry Sauce: In a small bowl, whisk together the chicken broth, 2 tablespoons of soy sauce, rice vinegar, brown sugar, and 1 teaspoon of cornstarch until smooth. Set this sauce aside. This ensures all the flavors are well combined and ready to be added to the wok or skillet.

3. Cook the Chicken: Heat 1 tablespoon of sesame oil and 1 tablespoon of olive oil in a large skillet or wok over medium-high heat. Once the oil is shimmering, add the chicken in a single layer, making sure not to overcrowd the pan. Cook for 3-4 minutes, flipping once, until the chicken is browned and cooked through. The chicken should have a nice golden crust. Remove the cooked chicken from the skillet and set it aside.

4. Saute the Aromatics and Harder Vegetables: Add the sliced onion to the same skillet and cook for 2-3 minutes until it starts to soften. Then, add the broccoli florets and sliced carrots. Stir-fry for another 3-4 minutes, until the vegetables are slightly tender-crisp. They should still have a bit of bite but be starting to soften.

5. Add Remaining Vegetables and Aromatics: Push the vegetables to one side of the skillet. Add the minced garlic and grated ginger to the empty side and cook for about 30 seconds until fragrant. Then, add the sliced red bell pepper and snap peas to the skillet. Stir-fry everything together for 1-2 minutes until the bell pepper and snap peas are bright and tender-crisp.

6. Combine and Finish with Sauce: Return the cooked chicken to the skillet with all the vegetables. Give the prepared stir fry sauce a quick whisk again (as the cornstarch can settle) and pour it over the chicken and vegetables. Stir continuously for 1-2 minutes, allowing the sauce to thicken and coat everything evenly. The sauce should become glossy and cling to the ingredients. Serve immediately, garnished with sesame seeds if desired.