Cut chicken into strips and then into chunks
Mince garlic
Add garlic, soy sauce, pineapple juice, ketchup, brown sugar, olive oil, sesame oil, water, cornstarch, salt and pepper to chicken and let marinate. Refrigerate for 1 hour.
Using metal skewers, layer your chicken, pineapple cubes, and veggies
Cook on grill at medium heat until chicken is tender and veggies are crispy
Keep basting while cooking