Bring broth and water to a boil in a medium soup pot. When it starts to boil, add the next 12 ingredients (plus chicken if using).
Cook over a medium-low flame for 45 minutes, or until rice is tender, semi-covered.
Taste for any seasonings adjustments and serve with cilantro, avocado cubes, and other optional toppings listed.
Add the broth and water to the pressure cooker, along with the next 12 ingredients (plus chicken if using). (Not the avocado, cilantro, or other optional toppings.) Stir well.
Pressure on high for 10 minutes. Let the pressure come down naturally - either fully if you're busy or for at least 10 minutes.
If you used whole chicken breast, remove and cube or shred and return back to the pot.
To serve, sprinkle with cilantro, chopped avocado. Top with optional ingredients listed, if using.