Heat 1-2 tablespoons of olive oil or butter in a deep skillet over medium heat. Add chopped onion (if using) and sauté for 2-3 minutes until translucent.

Stir in minced garlic and sauté for an additional minute. Then add cooked chicken and chopped chipotle peppers, mixing well.

Pour in chicken broth, scraping up any browned bits from the skillet, then add heavy cream, stirring gently.

Bring to a simmer and add uncooked penne pasta, ensuring it's submerged. Cover and cook for 10-12 minutes, stirring occasionally.

Reduce heat to low and add shredded cheddar cheese, stirring until melted and creamy.

Taste and adjust seasoning with salt or pepper. Let sit off heat for 2 minutes before serving.