Preheat your oven to 400°F (200°C). Spread the cubed butternut squash on a baking sheet, drizzle with olive oil, and toss with maple syrup, salt, and pepper. Roast for about 25-30 minutes until tender and caramelized, bubbling and slightly browned around the edges.
While the squash roasts, cook the chicken breasts in a skillet over medium heat until fully cooked through, about 6-8 minutes per side. Let rest for a few minutes, then shred with two forks into bite-sized pieces.
In a large pot, heat a tablespoon of olive oil over medium heat. Add the chopped onion and cook, stirring occasionally, until translucent and soft, about 5 minutes. Add the minced garlic and cook until fragrant, about 30 seconds.
Add the roasted butternut squash to the pot along with the chicken broth and diced tomatoes. Bring the mixture to a gentle simmer, allowing the flavors to meld and the soup to heat through, about 10 minutes.
Puree the soup using an immersion blender until smooth and velvety, or carefully transfer to a blender in batches. Return to the pot and stir in the shredded chicken, chipotle powder, and lime juice. Adjust seasoning with salt and pepper to taste.
Ladle the hot soup into bowls and garnish with chopped cilantro. Serve immediately, enjoying the warm, smoky sweetness and vibrant autumn hues.