Adjust oven rack to upper third of oven and preheat oven to 400 degrees. In a large mixing bowl, combine chicken thighs with olive oil. Season with salt, pepper, garlic powder, onion powder, smoked paprika, and brown sugar and toss to combine.
Place a large baking rack on a sheet pan. Line sheet pan with foil for easier clean up, if preferred. Place chicken thighs, skin side up on baking rack and place in oven. Bake for about 30 minutes, depending in size of chicken thighs, or until internal temperature reaches 175 degrees. While chicken thighs are baking prepare BBQ sauce.
Once chicken thighs reach 175, remove from oven and brush generously with BBQ sauce on both sides. Turn oven to broil and let sauce caramelize slight just for 3-4 minutes. Watch the chicken carefully to make sure the sauce doesn't burn. BBQ Chicken Thighs are ready to serve! Serve any additional BBQ sauce on the side.
In a small saucepan, stir together all ingredients and bring to a simmer. Reduce heat and let simmer, gently stirring occasionally while chicken is cooking.