Preheat oven to 450º. On a foil-lined baking sheet, toss sweet potato slices with olive oil, and season with salt and pepper. Arrange in a single layer.
Transfer potatoes to the oven and roast, flipping halfway through, until golden and just barely fork tender, about 20 minutes.
Top each potato slice with a sprinkling of sweetener and chopped pecans, dividing evenly. Return to the oven and roast until potatoes are glazed and pecans are toasted, 5 to 7 minutes. Serve immediately.