Heat oil in a large pot over medium heat. Add onion and celery and sauté until tender, about 8 minutes.
Add garlic, cumin and oregano and saute for a minute more.
Add broth, tomatoes, corn and chilies, season with salt and bring to boil.
Reduce the heat and simmer until corn is tender, for 5 minutes.
Drop in the chicken and simmer until cooked through, about 3 minutes.
Turn off the heat and stir in the black pepper, coriander and lemon juice.