1. 1. In a large skillet, heat some oil over medium-high heat.

2. 2. Add boneless chicken pieces and cook until browned and cooked through.

3. 3. Remove the chicken from the skillet and set aside.

4. 4. In the same skillet, add chopped bell pepper, broccoli, celery, and diced red-skinned potatoes.

5. 5. Cook the vegetables until they are slightly tender, but still crisp.

6. 6. Return the chicken to the skillet.

7. 7. Pour apple cider vinegar over the chicken and vegetables, and stir to coat everything evenly.

8. 8. Cook for another few minutes until the sauce thickens slightly.

9. 9. Serve hot and enjoy!