Cut the pumpkin into smaller pieces. Peel it, remove the seeds and pulp, then cut it into 2-3 cm cubes.
Place in a mixing bowl, season with salt and pepper, and add the dried oregano. Drizzle with olive oil and balsamic vinegar, then mix thoroughly.
Cut the apples into quarters, remove the core, then add them to the pumpkin mixture.
Peel the orange and cut it into larger segments, then mix it in with the pumpkin.
Transfer everything into an ovenproof dish and spread it out evenly. Set aside.
Clean the chicken thighs, then make a few cuts near the bone with a sharp knife so they cook through properly. Season with salt and pepper..
Heat olive oil and butter in a pan and sear the chicken thighs. Start by placing them skin-side down. Once a nice crust has formed, flip them and sear the other side as well.
Place the seared chicken thighs on top of the pumpkin mixture. You can deglaze the pan with a little water or even white wine. Bring it to a quick boil, then pour the juices over the chicken.
Cover with foil and bake in a preheated oven at 200°C (392°F) for about 50 minutes. For the last 5 minutes, bake without the foil to let it brown.