Heat oil in Dutch oven or large saucepan over medium-high heat until hot. Add chicken; cook and stir 4 to 5 minutes or until chicken is no longer pink.
Add carrots, green onions, bok choy, ginger, water and broth. Bring to a boil. Reduce heat to low; cover and simmer 5 minutes. Add pasta; cover and simmer 3 to 4 minutes or until pasta is tender. Stir in lemon juice.