Blend all the ingredients for the sauce in a blender or food processor for 10 seconds.
Taste the sauce and add your choice of sweetener to your liking.
Blend again for a few more seconds.
Heat the sauce in a large skillet on medium-high heat for 5 minutes. Carefully transfer the sauce to a heat proof bowl.
Rinse the skillet clean.
Season the chicken with salt and pepper.
Add the corn starch and massage the chicken with your hands.
If using fresh broccoli or green beans, boil the broccoli for 3-5 minutes until soft enough to pierce with a fork yet firm.
Transfer the vegetables to a plate lined with a paper towel.
Wipe down the skillet until dry.
Heat approximately 1 tablespoon of oil in the skillet on medium-high heat.
Cook the onion and chicken until the chicken is cooked through, approximately 3-4 minutes.
Add the remaining vegetables and stir-fry them together for 2 minutes.
Slowly add a few tablespoons of sauce while stirring the vegetables and chicken.
Continue to add the sauce a few tablespoons at a time, allowing about 15 seconds between each addition to allow sauce to slightly cook down.
Spoon the stir-fry over a bowl of hot rice. Serve immediately.