Preheat oven to 350 degrees, with racks in upper and lower thirds. Divide plantains between two rimmed baking sheets. Toss with oil, then arrange in a single layer on sheets. Season with salt and pepper. Bake until golden and crisp, 30 to 35 minutes, rotating sheets and flipping plantains halfway through. Drain plantains on paper towels.
To store, place cooled chips in an airtight container, up to 2 days.