Preheat oven to 425F and spread the carrots onto a baking sheet.
Drizzle the melted butter over the carrots and season with salt and pepper.
Bake at 425F until carrots are tender (about 25-30 minutes).
Toss the carrots in a medium bowl with 1/2 cup of balsamic vinegar, adding more if desired.
Add the chives and continue to toss until well-coated and season to taste with salt and pepper.