Season chicken thighs with salt and pepper, sear skin-side down in a large skillet over medium-high heat until golden, about 6 minutes. Flip and sear 2 minutes more, then remove.
Add onion to the skillet, cook until softened, about 5 minutes.
Add garlic, cook 30 seconds, then deglaze with white wine, scraping up browned bits.
Stir in chicken stock and Dijon mustard.
Return chicken to the skillet, skin-side up, add fresh herbs.
Cover and simmer 25-30 minutes until chicken is tender.