In a large pot or dutch oven, heat pot over medium heat with oil of choice (EVOO or coconut oil work best) Saute using onions and carrots. Stirring frequently. Add garlic, ginger, cumin & coriander. Saute for a few minutes. Add Japanese sweet potato, broth, coconut milk and lemongrass. Bring to a boil, then simmer covered for 15 mins (or until the sweet potatoes are cooked). Add corn and cauliflower.
With an immersion blender (remove lemongrass if left whole) blend 1/2 of the soup. Stir in cilantro, can of diced tomatoes, green onions, lime zest and juice and cooked shredded chicken. (Save some cilantro for garnish, lime wedge optional). Stir and serve.
To cook the chicken thighs in instant pot- chicken thighs + 1 cup liquid (water or broth) Manual High 10 minutes, Natural Pressure Release for 5 mins, then manual release.