Thinly slice the sweet potato (as thin as a regular potato chip), using a mandoline, if possible. Rinse the slices in cold water and pat dry.
Lightly coat the slices with olive oil and a sprinkle of salt. Lay them out in a single layer in the air fryer. Cook in batches, rather than crowd the basket.
Air fry at 350°F for about 10 minutes. After 5 minutes, shake the basket and space out the chips again. Watch the chips closely, checking every other minute, so they don't burn and remove them as soon as a little bit of brown starts to appear on the chips. They might still be a little flexible; they'll crisp as they cool.
Place on a cooling rack for a few minutes to cool and crisp up.
Notes
You don’t have to spray the basket with cooking spray, since the potatoes have olive oil on them.The cooking time will vary depending on the thickness of your slices. They can take anywhere from 8-12 minutes to finish cooking. After 5 minutes start watching them closely, to avoid burning and remove as soon as some brown appears. They might still be a little flexible in the middle, but they’ll crisp up when cooled. If you’re not sure, take one out of the basket and allow it to cool for 15 seconds to see if it crisps properly. If not, continue cooking.You can somewhat overlap the slices in the basket, but don’t pile them on top of each other or they won’t cook properly. Work in batches instead.