Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Cut the chicken breast and the peeled butternut squash into uniform one-inch cubes to ensure even cooking.
In a large mixing bowl, combine the chicken and squash cubes with the olive oil, sea salt, black pepper, rosemary, thyme, and garlic powder.
Toss the ingredients thoroughly until every piece is well-coated with the oil and aromatic herb blend.
Spread the mixture in a single layer on the prepared baking sheet, making sure not to crowd the pieces so they roast rather than steam.
Place the tray in the oven and roast for 20 to 25 minutes, tossing the contents halfway through the cooking time.
During the final 5 minutes of roasting, sprinkle the raw pepitas over the chicken and squash to let them toast until golden and fragrant.
Remove from the oven once the chicken is cooked through and the squash is tender with caramelized edges.
Divide into portions and serve immediately while the seeds are perfectly crunchy.