Heat olive oil in a large pot over medium heat. Add diced chicken and cook for 5-7 minutes until browned. Remove chicken and set aside.
In the same pot, add onion, garlic, bell pepper, carrots, and celery. Sauté for 5 minutes until softened.
Add chicken broth and bring to a boil. Add pasta and cook according to package instructions for 8-10 minutes until al dente.
Reduce heat to low, return chicken to the pot, and stir to combine.
Stir in heavy cream and Parmesan cheese. Season with salt, pepper, and optional cayenne pepper. Simmer for a few minutes to heat through.