Preheat the oven to 450 degrees. Line a baking sheet with a nonstick baking mat or parchment paper.
Slice pineapple crosswise into 1/4-inch slices, and place in a single layer on the baking sheet. Squeeze lime juice over pineapple slices. Combine the sugar, salt, and chili powder in a shallow dish. Coat each pineapple slice on both sides with sugar mixture and return to the baking sheet. Transfer pineapple slices to oven, and roast until very soft and beginning to brown, about 15 minutes.
Serve warm or at room temperature.