Preheat oven to 350.
Heat olive oil and 2 tablespoons butter in dutch oven over medium high heat.
Sprinkle chicken thighs with garlic powder, onion powder, salt, and pepper.
Add chicken thighs to dutch oven. Cover, and sear 3-4 minutes.
Flip chicken, cover and sear other side 3-4 minutes.
Remove chicken, set aside on plate.
Add onions, carrots, and celery to dutch oven.
Cook 4-5 minutes until slightly soft.
Add garlic cloves, cook additional 30 seconds.
Add remaining butter, then add flour, stir, and cook for several minutes until flour is aromatic and brown.
Add chicken stock. Stir.
Add red wine vinegar.
Add salt and pepper to taste.
Add chicken back into dutch oven, nestle the pieces between the veggies.
Cover and transfer to oven. Braise at 350 for 2 1/2 to 3 hours.
Remove from oven, allow to rest for a couple minutes. Serve over rice or mashed potatoes.