Cook penne noodles according to package directions until tender but not overcooked.

Rinse the cooked noodles under cold water to stop the cooking process and prevent sticking.

Melt butter (or margarine) in a large pan over medium heat.

Add the cooked and rinsed noodles back into the pan with the melted butter.

Drizzle olive oil over the noodles and toss to coat.

Add basil pesto to the noodles and toss well to combine.

Add the cooked chicken breast chunks to the pan.

Toss all ingredients together until the chicken is evenly coated with the pesto sauce.

Serve immediately.

Garnish with finely grated mozzarella cheese, if desired.