Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Cut the chicken breast and the peeled butternut squash into uniform 1-inch cubes to ensure even cooking.
In a large mixing bowl, combine the chicken, squash, olive oil, minced garlic, chopped fresh sage, sea salt, and black pepper.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces are not crowded.
Roast for 20-25 minutes, tossing halfway through, until the chicken is cooked through and the squash is tender and caramelized.
While the chicken and squash roast, place the kale in a bowl and drizzle with lemon juice, massaging it with your hands for 1 minute until softened.
Divide the massaged kale into bowls and top with the hot roasted chicken and butternut squash mixture.