Preheat the oven to 375º F.
Heat 2 tablespoons of EVOO in a large skillet over medium-high heat. Add the chopped chicken chunks and sauté them on both sides until golden brown. Remove chicken chunks from skillet and reserve on a plate.
Add another 2 tablespoons of EVOO, the onion, carrot, celery and garlic to the same skillet and cook, stirring occasionally, until the vegetables are tender, 5-6 minutes.
While the veggies are cooking start the sauce: In a medium-size sauce pan, melt the butter over medium-high heat then stir in the flour and cook until light brown, about 1 minute. Whisk the chicken stock and hot sauce into the butter/flour mixture and bring it to a boil. Simmer the gravy until thickened, 2-3 minutes.