Preheat oven to 375 degrees. Line a large rimmed baking sheet with parchment paper

Slice the buns in half. Place the bottom halves of buns in baking sheet. Scatter half the cheese over the buns.

Split each hot dog in half lengthwise; lay them side-by-side over the cheese. Cover with chili, remaining cheese, onions, and top buns.

Brush tops of buns with melted butter and sprinkle with garlic powder.

Bake until cheese has melted and buns are slightly toasted, about 15 minutes. Garnish with chives and serve immediately.