Preheat oven to 300°F. Slice sweet potato into thin slices with a mandolin or knife. Place in large bowl. Drizzle with oil and sprinkle with Italian seasoning and sea salt; toss to coat well.
Place sweet potato slices in single layer on large shallow foil-lined baking pans. (You will need to prepare in 2 or 3 batches.)
Bake one pan at a time 25 to 30 minutes or until crisp, rotating pan halfway through cook time. Cool on wire rack 10 to 15 minutes.