Preheat oven to 400°F. Season the chicken with the garlic powder, salt, and pepper. Add the seasoned chicken, tomatoes, shallot, thyme, and olive oil to an oven-safe 9x13-inch baking dish and toss to combine. Arrange the block of feta in the middle of the baking dish. Flip to coat with the olive oil. Bake for 30 minutes or until the tomatoes burst and the feta is golden brown. While the chicken mixture is baking, prepare the penne according to the package directions.