Begin by cooking the penne pasta according to package instructions. Once it’s al dente, drain it using a colander, rinsing with cold water to stop the cooking process. Set the drained pasta aside.

In a large skillet or saucepan, heat the olive oil over medium heat. Once hot, add the diced onion and sauté until it becomes translucent and fragrant, around 3-5 minutes.

Add the minced garlic to the pan and stir with the onions, cooking just until fragrant, about 1 minute.

Incorporate the butter into the skillet. Once melted, add the chicken broth and heavy cream, stirring well to combine. Bring the mixture to a gentle simmer.

Stir in the shredded rotisserie chicken and broccoli florets, allowing everything to cook together for a few minutes until the chicken is heated through and the broccoli is tender.

Add the grated Parmesan and mozzarella cheese, stirring until melted and fully combined. Season with Italian seasoning, garlic powder, red pepper flakes, salt, and black pepper to taste.

Finally, add the cooked pasta to the skillet and toss everything together until the pasta is well coated with the creamy sauce.