Preheat your oven to 350°F (175°C).

In a large oven-safe skillet or casserole dish, heat the olive oil over medium heat. Add the diced onion and minced garlic. Sauté for a few minutes until they become fragrant and translucent.

Stir in the long-grain white rice and cook for another 2-3 minutes, allowing the rice to slightly toast.

Add the butternut squash cubes and continue to cook for another 2-3 minutes, stirring occasionally.

Pour in the can of cream of mushroom soup and the vegetable stock. Stir well to combine all the ingredients. Season with salt and pepper to taste. Stir in chicken.

Add the chopped broccoli and shredded chicken on top of the mixture, distributing it evenly. Taste the mixture and add more salt as needed.

Cover the skillet or casserole dish with a lid or aluminum foil.

Place the covered skillet or dish in the preheated oven and bake for 45-50 minutes, or until the rice is tender, and the liquid is absorbed. Check the casserole after about 30 minutes and add a bit more vegetable stock if needed.

If desired, you can sprinkle grated cheese on top during the last 10-15 minutes of baking for a cheesy topping.

Once the casserole is cooked to your liking, remove it from the oven, and let it sit for a few minutes before serving.

Serve the butternut squash and broccoli casserole as a side dish or a vegetarian main course. Enjoy!