In a medium sized bowl, whisk together olive oil, vinegar, Dijon mustard, honey, garlic, chives and salt and pepper. Brush marinade over both sides of the chicken breasts and put in the fridge to marinade until you are ready to grill.
Place chicken on either your barbecue or indoor grill and grill until temperature reaches 165°F with a meat thermometer. I used an indoor grill and it took about 10 minutes. Place on a serving platter.
In the meantime, make the sauce by stirring together the Dijon mustard and honey together in a bowl. Spread sauce over the chicken and serve.
Notes
I served our chicken with some steamed asparagus. Delish!