1. Heat oil over medium-high heat. Add chicken and cook about 6 minutes, until browned on both sides.
2. While chicken is cooking, stir together jam and mustard in a small bowl.
3. Spread jam mixture over the tops of the chicken pieces and sprinkle with blueberries.
4. Reduce heat to medium-low, cover and cook about 15 minutes, or until juices run clear from chicken.
5. Remove chicken and blueberries to plate with a slotted spoon.
6. Add vinegar to the pan, increase heat to high, and bring sauce to a boil.
7. Boil uncovered, stirring occasionally, until sauce is reduced by about 1/3 (about 5 minutes).
8. Pour sauce evenly over chicken and enjoy!