Heat olive oil in a large pot or deep skillet over medium heat.
Add sliced kielbasa sausage and cook for 4 to 5 minutes until browned on both sides. Remove sausage from the pot and set aside.
In the same pot, add diced onion and cook for 3 to 4 minutes until softened.
Add minced garlic and cook for 30 seconds until fragrant.
Pour in the diced tomatoes with their juice and chicken broth. Stir to combine.
Add uncooked penne pasta, dried Italian seasoning, crushed red pepper flakes, salt, and black pepper. Stir well.
Bring the mixture to a boil, then reduce heat to medium-low. Cover and simmer for 12 to 15 minutes, stirring occasionally, until the pasta is tender and most of the liquid is absorbed.
Return the browned kielbasa to the pot and stir in heavy cream, mozzarella cheese, and Parmesan cheese.
Cook for an additional 2 to 3 minutes, stirring frequently, until the cheese is melted and the sauce is creamy.
Remove from heat and sprinkle with chopped fresh parsley before serving.