Heat oil in a large pot over medium heat; add onion and garlic and cook until fragrant. Stir in ginger and fish sauce; cook for 1 minute before adding chicken. Brown chicken for 5 minutes. Add broth and water and bring to a simmer. Add chayote and simmer until chicken is cooked through about 15-20 minutes. Season with salt and pepper. Add bok choy and spinach; cook for 1-2 more minutes. Makes 8 servings.
Approximate Nutrient Analysis per serving (not including salt to taste):
220 calories, 9 g fat, 2 g saturated fat, 125 mg cholesterol, 750 mg sodium, 8 g carbohydrate, 3 g fiber, 4 g sugar, 27 g protein