Cook pasta according to package directions, omitting salt and fat; drain and set aside.
While pasta cooks, heat oil in a large saucepan over medium-high heat until hot. Meanwhile, cut chicken into 1-inch pieces. Add chicken and garlic to skillet; cook 5 minutes or until chicken is done, stirring occasionally. Add broth, tomatoes, and crushed pepper; bring to a boil. Reduce heat, and simmer, uncovered, 5 minutes.
Add pasta and spinach to saucepan. Cook 2 minutes or until spinach wilts, stirring occasionally. Ladle stew into individual bowls; sprinkle evenly with cheese.