Place the cubed chicken in a large ziptop bag or container with an airtight lid. Add the BBQ sauce and toss together to coat all of the chicken evenly with the sauce. Refrigerate for at least two hours or overnight.
*If you are using bamboo skewers, submerge them in water and set aside for at least 30 minutes before grilling to prevent them from burning. If you are using metal skewers, you can skip this step.
When the chicken is finished marinating, prepare your veggies. Peel and slice your onion into 1-2 inch pieces (no more than 2 or 3 onion layers per piece) to make 18 even pieces. Place your onion into a medium mixing bowl and add the zucchini rounds, olive oil, garlic powder, salt and pepper. Toss together so veggies are coated in the spices and olive oil.
Prepare your skewers. Start with a piece of marinated chicken, rotate adding the chicken, onion, and zucchini to fill the skewer, and then ending with a piece of chicken. There will be 4 pieces of chicken, 3 pieces of onion and 3 pieces of zucchini per skewer.
Grill the skewers over medium/high heat for 15-18 minutes, until the internal temperature of the chicken reaches 165 degrees and the veggies are crisp-tender.
This recipe makes 6 servings. Each skewer is one serving, which is made up of 4 pieces of chicken, 3 pieces of onion and 3 pieces of zucchini per skewer.