Set oven to 400 degrees F.
Begin by slicing very thin slices of sweet potatoes.
Spray cookie sheet with avocado oil spray or brush with oil.
Layer sweet potato slices over the cookie sheet in one layer and spray or brush with oil (overlapping potatoes slightly is fine).*One large potato will cover at least one cookie sheet. Use a second sheet and cook at the same time to save cooking time. Bake at 400 degrees for 12-15 minutes. Rotate trays halfway through cooking time. Potatoes will be ready when they are soft, curling up on the sides, and even browning a touch on the sides.
While the potatoes are cooking, put ground beef in a skillet and brown. Add 2 tablespoons of taco seasoning toward the end of cooking (or a packet if that is your preference).
While the meat and potatoes cook, prepare your toppings.
Assemble as soon as everything is finished cooking.