Preheat the oven to 400°F (204°C).

In a large oven-safe skillet, heat the olive oil over medium heat.

Season the chicken thighs with salt, pepper, garlic powder, and thyme.

Add the seasoned chicken thighs to the skillet, cooking for about 5 minutes on each side until golden brown.

Remove the chicken from the skillet and set it aside. In the same skillet, add the sliced onions and sauté for 2-3 minutes until they begin to soften.

Next, add the apple sausages, diced apples, and halved Brussels sprouts, stirring to combine.

Return the chicken thighs to the skillet, placing them on top of the mixture.

Transfer the skillet to the preheated oven and roast for 25-30 minutes.

Once cooked, check that the internal temperature of the chicken has reached 165°F (74°C).

Remove from the oven, let it rest for 5 minutes, then serve warm.