Bring a large pot of lightly salted water to a boil. Add penne and cook, stirring occasionally, until tender yet firm to the bite, about 11 minutes. Drain and return to the pot.
Meanwhile, heat olive oil in a large pan over medium-high heat. Add chicken sausage and onion. Cook until chicken is browned and no longer pink in the center, 5 to 7 minutes. Reduce heat to low and mix in pesto. Add tomatoes with juice and chicken broth. Simmer sauce until slightly reduced, 5 to 10 minutes.
Pour cream into the sauce. Simmer until reduced to your desired thickness, 5 to 10 minutes. Pour sauce into the pot of cooked penne. Mix thoroughly. Let rest for 5 minutes before serving. Garnish with shredded Parmesan cheese to your liking.
