Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Carefully slice the kabocha squash in half, scoop out the seeds with a spoon, and cut into 1-inch thick wedges.
Cut the chicken breast into 1-inch cubes so they cook at the same rate as the squash wedges.
In a large mixing bowl, combine the squash wedges and chicken pieces with olive oil, rosemary, thyme, sea salt, and black pepper.
Toss everything together until the chicken and squash are evenly coated in the oil and herbs.
Spread the mixture in a single layer on the prepared baking sheet, making sure not to overcrowd the pan.
Roast for 25 to 30 minutes, flipping the pieces halfway through, until the squash is fork-tender and the chicken is fully cooked.
While the tray is roasting, place the kale in a small bowl with the lemon juice and a tiny pinch of salt, then massage with your hands for 1 minute until soft.
Plate the massaged kale and top with the hot roasted kabocha squash and herb chicken.