Heat the oil in a deep skillet over medium heat. Add the chicken sausage, and cook until browned on either side. Add the peppers to the skillet, and cook until softened, about 5 minutes. Stir in the onions and garlic, and cook until fragrant, about 2 minutes.
Add the rotini and chicken stock, making sure the pasta is submerged. Bring to a boil, and cook until the rotini is tender and al dente, about 10 minutes.
Once the pasta is soft and the liquid has reduced, add heavy cream and stir. Simmer until thickened slightly, about 5 minutes. Remove from the heat, and stir in the Parmesan. Season to taste with salt and pepper, and serve.