Heat 2 Tbsp of olive oil in medium skillet to medium high heat. Season chicken with salt and pepper and place chicken in skillet to cook, about 3-4 minutes per side or until an internal temperature of 165° F is reached.
Meanwhile, cut off both ends of the onion, chop the onion in half and peel off unwanted outside layers. Slice into long, thin strips. Put the onion and garlic, along with two tablespoons of olive oil into the frying pan for now.
Chop the broccoli and cauliflower into small pieces to measure out about 2 cups each. Using a peeler, slice the carrot into long thin strips. Thinly slice the mushrooms and bok choy. Combine the broccoli, cauliflower, carrots and mushrooms in a large bowl.
Turn on the frying pan with the onion and garlic to medium heat. Stir and fry the onions and garlic for about 7 minutes.
Add the broccoli, cauliflower, carrots and mushrooms. Let it cook while stirring for 5 minutes.
Meanwhile in a small bowl, add the soy sauce, cornstarch, cooking wine, sesame oil, rice vinegar, tahini, sugar-free syrup, ginger powder and red pepper flakes together. Stir until everything is mixed evenly.
After about 5 minutes of cooking the vegetables, add the chicken, bok choy, the sauce mix and stir, cooking for a final 8-10 minutes. Make sure to stir constantly so the bottom doesn’t burn.