In a large dutch oven or heavy stock pot, heat up the avocado oil on medium heat and saute the garlic, onion and garlic for about 5 minutes.
Season the chicken legs with salt and pepper and add the chicken legs and brown on all sides.
Add the fish sauce and let cook for 2-3 minutes.
Add the water and the Bouillon. Cover and and let it come to a boil.
Remove the scum that has floated up to the top and reduce the heat to a simmer.
Let it simmer for 10 minutes.
Add the chayote that has been cut up and let it cook for about 5 more minutes or until the chayote is easily cut with a fork.
Turn off the heat on the stove and add the spinach. Mix well.
Serve with white rice and a side of fish sauce.