In a bowl, whisk together the marinade ingredients.
Place chicken cubes in a large bowl or zip-top bag. Pour marinade over chicken and toss to coat. Marinate in the refrigerator for at least 30 minutes, or up to 4 hours.
Preheat grill to medium-high heat. Thread chicken, bell peppers, and red onion onto skewers.
Grill kabobs for 12-15 minutes, turning occasionally, until chicken is cooked through and vegetables are tender.
Notes
Serve with a side of tzatziki sauce and warm pita bread for a complete meal!