Preheat oven to 400°F.
Pour the tomatoes into a large bowl. Add the zucchini, basil, cheese, olive oil, garlic, salt, and pepper. Stir to combine.
Meanwhile, bring the chicken broth to a boil in a medium saucepan over high heat. Add the orzo and cook for 4 minutes (I think you can even reduce this amount depending on the thickness of your orzo because the orzo really expands when it's cooked in the peppers). Do not fully cook.
While the pasta cooks, prepare the peppers by cutting off the tops and scooping out the ribs and seeds.
Pour the orzo/chicken broth into a strainer set above a 3 quart baking dish so that the broth collects in the dish. Transfer the orzo to the large bowl with the vegetables. Stir the orzo into the vegetable mix to combine.
Fill the peppers with the orzo mixture and place in the baking dish containing the warm chicken broth. Cover the dish and bake for 45 minutes. (If using less than 6 peppers and you have leftover orzo, put it in a covered casserole dish and bake alongside).
Remove the foil and sprinkle the top of each pepper with Parmesan cheese. Continue baking uncovered until cheese is golden, about 15 additional minutes.
Remove from oven and carefully transfer peppers to serving dish. Garnish with extra fresh basil if desired.