Cut the chicken into 1-inch or bite size pieces.
In a large bowl, add the olive oil, lemon juice, minced garlic, oregano and salt and pepper. Mix in the chicken and *let marinate for at least 30 minutes in the fridge, tossing every 10 minutes.
Cut up the veggies into chunks and set them out to string the skewers.
Once the chicken has marinated, thread the chicken pieces, red onion pieces, bell pepper pieces, and zucchini pieces onto skewers.
Grill for 10-15 minutes, rotating 2 or 3 times, until chicken is cooked through and veggies have softened. Grilling time may vary depending on heat on the grill and size of the chicken pieces.
Prepare side salad.
Serve Garlic Chicken Kebabs with side salad.