If you don't have a smoker, create a foil pouch with 2 cups soaked and drained wood chips. Place on the stovetop over high heat until smoking. Carefully place the pouch in a large cast-iron skillet, cover with a cooling rack, and pile cut and seasoned sweet potatoes in the center of the rack. Place a second, inverted cast-iron skillet over the potatoes to create a lid. Smoke for 20 minutes, then transfer to a 375-degree oven to finish cooking, another 10 minutes.