Bring a large pot of lightly salted water to a boil. Place pasta shells in the pot, cook for 8 to 10 minutes, until al dente, and drain.
meanwhile, heat the olive oil in a frypan over medium heat, and cook the onion and garlic until tender. Mix in the zucchini, and season with oregano, salt and pepper, and chilli flakes. Cook 10 minutes, until tender.
Stir the chicken stock into the frypan, and cook 5 minutes, until heated through. Mix in the chicken, roasted red capsicums and cream cheese, and continue cooking 5 minutes. Serve over the cooked pasta, and top with fresh basil and Parmesan cheese.