Cook the pasta in a large pot of boiling salted water until al dente. Drain and set aside.
In the same pot over medium-high heat, sauté the olives and capers in the oil for about 1 minute. Add the tomato juice. Bring to a boil and reduce by half. Add the ratatouille, parsley and pasta. Continue cooking, stirring frequently, until heated through. Adjust the seasoning. Add the bocconcini or the chicken.