If using wooden skewers, soak them in water for 20 minutes while you prepare the chicken.
Preheat the oven to 450°F. Line a rimmed, broiler-safe baking sheet with foil.
In a large bowl, whisk together the olive oil, salt, pepper, garlic powder, onion powder, and thyme.
Cut the chicken breasts into cubes. Add the cubes to the bowl and toss with the seasoned olive oil.
Thread the coated chicken cubes on skewers.
Place the kabobs on the prepared baking sheet. If you use wooden skewers, place thin foil strips on their exposed edges to prevent them from burning. Bake the kabobs until cooked through, for about 15 minutes.
Switch the oven to broil. Place the baking sheet under the broiler, and broil the chicken just until browned, for about 1 minute. Serve immediately.
Video
Notes
You can add the chicken pieces to the marinade a few hours ahead. Cover, refrigerate, and allow them to marinate. But it's also OK to skip the marinating and bake them immediately after coating them in the oil and spice mixture. That's what I usually do.
Since ovens vary, you should use an instant-read thermometer to ensure the chicken is done. It should reach an internal temperature of 165°F.
You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. Reheat them gently, covered, in the microwave at 50% power. They're also good cold as a salad topping.