Preheat oven to 375F (190C) and lightly grease a 9x13 inch baking dish.

In a large bowl, toss the diced chicken breast with olive oil, minced garlic, and dried oregano until evenly coated.

Spread the seasoned chicken into the prepared baking dish. Top evenly with chopped red bell pepper, diced red onion, cherry tomatoes, and kalamata olives.

Bake uncovered for 25 minutes, or until the chicken is cooked through and reaches an internal temperature of 165F.

Remove from the oven, sprinkle crumbled feta cheese over the top, and return to the oven for 5 more minutes until the cheese softens. Serve warm.