Brown chicken on all sides in batches (about 8 minutes per batch).
Drain the fat, but reserve 1 tablespoon and return the pot to heat.
Cook garlic, tomatoes and oregano about 30 seconds.
Add wine and scrape up the browned bits for 1 minute.
Add broth and chicken to the pot and bring to a boil. Reduce to a simmer, cover and cook for 15 minutes.
Add the zucchini and season again with salt and pepper.
Cover and simmer for an additional 15 minutes before stirring in lemon juice.
Meanwhile, combine 4 1/2 cups of water, 1 1/2 tsp salt and 1/4 tsp pepper in a large saucepan and bring to a boil. Slowly whisk in cornmeal. Reduce heat to medium-low and cook, whisking frequently for 20-25 minutes. Whisk in butter.