Melt the coconut oil in a large saucepan over medium-low heat. Add the green onions, garlic, ginger, lemongrass, and chile. Cook, stirring continuously to avoid burning the garlic and ginger, for 2 minutes. Raise the heat to medium and stir into the broth, mushrooms, coconut milk, fish sauce, lime juice and salt. Add the chicken and bring to a boil. Reduce the heat and simmer, uncovered, until the chicken is no longer pink and the internal temperature registers 165 degrees F., about 15 minutes.
Remove the chicken from the soup and let it rest for 2 minutes. Remove the lemongrass pieces. Use two forks to shred the chicken into chunks, then return the chicken to the soup. Serve the soup with fresh cilantro and lime wedges.
Notes
To prepare lemongrass: cut off the woody root tip of each stalk until the purplish-tinted rings begin to show. Remove the loose, dry outer layers and use only the faintly colored, dense inner stalk that holds together when cut into shorter segments or rings.
To prepare as a Whole 30 approved recipe: be sure to use Whole 30 approved chicken broth and straw mushrooms.