Heat a large skillet over medium heat and add in the olive oil. Once hot, add in the chicken sausages and onion and cook until sausages are browned and onion is tender.
Season with salt, red pepper flakes and garlic and cook until fragrant, about 1 minute. Pour in the chicken broth, scraping the bottom of the pan to release any browned bits. Bring mixture to a boil then add in the uncooked pasta. Stir frequently, for about 10 minutes, until pasta is mostly tender, then add in the chopped zucchini.
Continue cooking an additional 3 minutes until zucchini is tender and most of the chicken broth is absorbed into the pasta. Stir in the lemon juice, 3 tbsp of the parmesan cheese and the grape tomatoes.
Remove from heat and top with the fresh basil and remaining 1 tbsp of Parmesan cheese. Enjoy!