Stir together the Greek yogurt, ½ cup basil pesto and garlic in a medium bowl. Season to taste with salt and pepper. Place chicken in the bowl and stir to coat. Cover and refrigerate for at least 2 hours or up to 8-10 hours. (I did about 10 hours, and it was seriously moist chicken!)
Preheat grill to medium high heat.
When ready to assemble, place cherry tomatoes in a small bowl with the remaining 2 tablespoons pesto and stir to coat. Alternate chicken and tomatoes on skewers. Sprinkle kebabs with salt and pepper. Lightly oil grill grates and grill for 3 minutes on one side, turn skewers and finish grilling for another 2 minutes or until chicken is cooked through.
If you’re using wooden skewers like I did, make sure you soak them in water for at least 30 minutes before using them on the grill.