Pat the chicken thighs dry and season them with salt and pepper. Heat olive oil in a large Dutch oven over medium-high heat. Place the chicken skin-side down and sear until golden brown, about 5 minutes per side, then remove and set aside.
Add the chopped onion to the same pot and cook until translucent and fragrant, about 3 minutes. Then, add the fennel seeds and cook for another minute until they release their aroma.
Stir in the turmeric powder and cook briefly to toast the spice, which will turn a vibrant golden color and smell warm and earthy.
Grate the orange zest directly into the pot, then squeeze in the juice of one orange, and stir everything together.
Return the seared chicken thighs to the pot, placing them in the aromatic sauce. Pour in the chicken broth, covering the chicken about halfway.
Bring the mixture to a simmer, cover with a lid, and reduce the heat to low. Let it cook gently for about 45 minutes, until the chicken is tender and falling off the bone.
Remove the lid and turn up the heat slightly to allow the sauce to thicken slightly, about 5-7 minutes. Taste and adjust seasoning with salt and pepper as needed.
Gently stir the chicken pieces to coat with the flavorful sauce, then serve hot with the aromatic braised sauce spooned over. Enjoy the tender meat with the bright, spiced broth.