Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper.
Wash and dry the potatoes. Slice them into 1/2-inch rounds and put them into a bowl. Drizzle in the olive oil; add 1 tablespoon chives, salt, and pepper, and toss to coat well. Arrange the potatoes separately on the baking sheet. Roast until the potatoes are cooked through, about 35 to 40 minutes. Remove from the oven and set aside to cool.
In a small bowl, mix the sour cream and horseradish.
To assemble, top the roasted potatoes with a dollop of the sour cream mixture and a sprinkling of chives. Add a small amount of caviar with a plastic spoon. Serve at room temperature.
Do not use a metal spoon for the caviar.