Preheat oven to 350° F. In a large ovenproof skillet, heat oil over medium-high heat. Brown chicken on both sides. Remove from pan. In the same pan, heat butter over medium-high heat. Add onion; cook and stir until tender, about 1 minute.
Stir in barbecue sauce, brown sugar, vinegar and honey. Bring to a boil. Reduce heat; simmer, uncovered, until thickened, about 4-6 minutes. Return the chicken to the pan. Bake until a thermometer reads 165° F, 12-15 minutes. Stir in strawberries and serve.