In a cast iron skillet over medium-high heat add the olive oil.
Sprinkle the chicken thighs on all sides with salt, pepper and flour.
Cook the chicken thighs until browned on all sides, about 3 minutes per side. Remove, and set aside.
Reduce heat to medium-low, add the onions and caramelize over medium heat until golden brown, about 10 to 15 minutes.
Stir in the garlic then add ½ cup brown ale, balsamic vinegar, honey and chili sauce. Simmer until reduced and thickened. Add the chicken back to the pan along with the remaining ½ cup brown ale.
Cover loosely with a lid, lower heat to maintain a simmer and allow to cook until chicken is cooked through, about an additional 10 minutes. Turning once during cooking.