Cook chicken in water until cooked through. Shred or dice.
In a large pot, heat oil over medium heat. Add onion and cook until softened, about 5 minutes.
Add garlic and cook for 1 minute more.
Add stock, butternut squash, cooked chicken, cumin, oregano, salt, and pepper. Bring to a boil, then reduce heat and simmer for 15-20 minutes, or until squash is tender.
Stir in cilantro and lime juice. Serve immediately.