Position a rack in the center of the oven; preheat to 425 degrees F. Lightly oil a rimmed baking sheet.
Combine the butter and garlic in a large microwave-safe bowl. Cover with plastic wrap and microwave to melt the butter, about 1 minute. Whisk in the Dijon and 1/4 teaspoon of the cayenne.
In another large bowl, combine the panko, Parmesan, chives, paprika and the remaining 1/4 teaspoon cayenne. Sprinkle the chicken thighs with 1/2 teaspoon salt. Dip the chicken in the mustard mixture to coat and roll in the panko on all sides. Arrange on the prepared baking sheet so the pieces do not touch.
Bake on the center oven rack until the coating is browned and crispy and the chicken is no longer pink near the bone, about 40 minutes.
Transfer to a large platter and serve.
This recipe is also delicious with boneless skinless chicken thighs. Prepare the thighs the same way and reduce the baking time by about 5 minutes, or until the internal temperature reaches 165 degrees F.