Preheat oven: Set to 400˚F (200˚C). Line a baking sheet with parchment paper or a silicone mat.
Slice potatoes: Cut 1 medium sweet potato into very thin rounds (about 1/16 inch). For the crispiest chips, keep the slices as thin and even as possible. Pat dry with paper towels if they seem moist.
Toss with oil and salt: Coat slices lightly with 1 tablespoon avocado oil or olive oil and a pinch of sea salt.
Arrange on pan: Spread slices in a single layer without overlapping.
Bake and flip: Bake 15 minutes, then flip and bake 5–10 minutes more. Watch carefully during the final minutes since smaller slices can brown much faster than larger ones.
Cool before serving: Let chips sit on the pan for a few minutes—they’ll crisp as they cool.