Preheat the oven to 400 degrees F (200 degrees C). Lightly coat a 9x13-inch baking pan with cooking spray.

Arrange potatoes in prepared baking pan; season with salt and pepper.

Roast potatoes in the preheated oven until easily pierced with a fork, 25 to 35 minutes. Let cool, 10 to 15 minutes.

Cook bacon in a large skillet over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain on paper towels. Crumble into smaller pieces.

Combine 3/4 cup cheese, onion, sour cream, mayonnaise, and most of the chives in a large bowl. Stir in potatoes and crumbled bacon. Garnish with remaining 1/4 cup cheese and chives.

Refrigerate salad 4 hours to overnight before serving.