In 3-quart saucepan, heat oil over medium-high heat. Add chicken and leeks; cook 5 minutes, stirring frequently.
Stir in tomatoes and broth. Heat to boiling. Reduce heat; simmer uncovered 10 minutes.
Add pasta; simmer uncovered 3 to 5 minutes or until pasta is tender and chicken is no longer pink in center. Serve with cheese.