Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Slice the yellow squash into half-inch thick half-moons and cut the chicken breast into one-inch bite-sized pieces.
In a large mixing bowl, combine the squash, chicken, minced garlic, olive oil, dried oregano, sea salt, and black pepper.
Toss the ingredients thoroughly until the chicken and squash are evenly coated in the oil and spices.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces are not overcrowded.
Roast in the oven for 18 to 20 minutes, or until the chicken is cooked through and the squash is tender with caramelized edges.
Remove from the oven and immediately sprinkle with the parmesan cheese and finely chopped fresh parsley before serving.