Preheat your oven to 400 degrees. Spray a baking sheet with nonstick spray. Scrub your sweet potatoes clean and lay them on the baking sheet. Roast in the oven until soft, somewhere in the range of 1 hour. Actual baking time will depend on thickness and size of your potatoes. Start checking them after 40 minutes if they are on the small side.
Remove the sweet potatoes from the oven and carefully slice them in half. Scoop out the flesh and put it in a medium-sized mixing bowl. Leave a little flesh on the potato to create a wall. Set the skins aside.
Once the flesh has been removed, mash it all up in the mixing bowl. Add in the lime juice, minced garlic, cumin, chili powder, and minced chipotle and mix until combined. Stir in the spinach. The potatoes should still be hot enough to wilt them as they are mixed in.
Line the skins up on the baking sheet. Stuff them with the chipotle sweet potato mixture and top with cheese and cilantro. Put them back in the oven for about 20 minutes until cheese is bubbling and starting to brown.