Dredge the chicken thighs in flour and season with salt and pepper.
In a large high-rimmed saute pan, cook the sausage until browned on both sides. Remove sausage from pan.
Add more oil to the pan if needed, then add the floured chicken thighs and brown on both sides. Remove chicken from pan.
Add the onions to the pan and cook until translucent. Add the garlic and pickled peppers with the pickling liquid.
Turn off the heat, then add the white wine. Turn the heat back on and let the wine reduce for a couple minutes.
Add the chicken broth and the herb bundle. Bring to a boil, then reduce to a simmer. Add the chicken and sausage back to the pan.
Braise the chicken and sausage until the sauce thickens and the chicken is tender, about 30 minutes.
Remove the herb bundle. Taste the sauce and adjust seasoning with more vinegar, salt, and pepper as needed.
Turn off the heat and stir in the cold butter until melted. Stir in the fresh parsley.
Roast the halved fingerling potatoes at 450°F for 15-20 minutes, flipping halfway, until crispy.
