Heat the oil in a skillet over medium-high heat. Cook the chicken breasts in the hot oil until golden brown on both sides, about 5 minutes total. Stir in the garlic, olives, and grapes; cook and stir 1 minute.
Sprinkle the chicken breasts with feta cheese.
Pour the wine into the pan and bring to a boil. Cover and cook until the cheese has melted and the sauce reduced by half, about 5 minutes more.