Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Dice the chicken breast and butternut squash into uniform 1-inch cubes to ensure they cook at the same rate.
In a large mixing bowl, combine the chicken, squash, olive oil, dried rosemary, garlic powder, sea salt, and black pepper, tossing until everything is evenly coated.
Spread the mixture in a single layer on the prepared baking sheet, ensuring there is space between the pieces for proper browning.
Roast for 20 to 22 minutes, or until the squash is tender and the chicken is cooked through to an internal temperature of 165°F.
Remove the sheet from the oven, add the kale to the pan, and toss gently with the warm ingredients for 2 minutes until the kale is slightly wilted.
Transfer to a plate and serve immediately while the squash is hot and golden.