Preheat your oven to 400°F (200°C). Pat the chicken thighs dry and season them generously with salt, pepper, and a sprinkle of sage. Heat the skillet over medium-high heat, add olive oil, and place the chicken skin-side down. Sear until the skin is golden and crispy, about 6-8 minutes. Flip and cook for another 2 minutes to start rendering the fat.
Remove the skillet from heat and scatter chopped garlic and red pepper flakes over the chicken. Toss in the sliced apples and chopped vegetables around the chicken, arranging everything in a single layer for even roasting.
Drizzle honey over the apples and vegetables for a touch of sweetness, then season everything with additional salt, pepper, and a pinch more sage. Transfer the skillet to the preheated oven and roast for about 25-30 minutes, until the chicken skin is crisp, the internal temperature reaches 165°F, and the vegetables are tender and caramelized.
Once cooked, remove the skillet from the oven and let it rest for 5 minutes. Use tongs to serve the chicken alongside the roasted apples and vegetables, ensuring each plate has a good mix of textures and flavors.
Finish with an extra sprinkle of fresh herbs or flaky sea salt if desired, then enjoy the warm, crispy chicken contrasted with the sweet, tender fall produce.