In a large skillet over medium-high heat, heat olive oil until shimmery. Add chicken, onion, and garlic and saute several minutes until chicken is no longer pink. Stir in flour until smooth. Slowly add milk, stirring constantly until smooth. Add cream, chicken broth, and pasta. Bring pasta to a simmer over medium-high, then reduce heat to medium and let simmer 10-15 minutes, stirring occasionally until most of the liquid is evaporated and pasta is tender and creamy. (if pasta isn't cooking fast enough, add a little more chicken broth near the end)