Preheat oven to 425 degrees F.
Place the sweet potatoes on two large baking sheets and toss with olive oil. Bake for 30 minutes or until desired crispiness.
Remove sweet potatoes and place them all on one baking sheet. They will have shrunk up in the oven a bit so you'll just use one baking sheet to load up all the toppings. Add the meat (if using), black beans and shredded cheese and place back in the oven for 5 minutes or until cheese is melted.
Remove pan from oven and add jalapeños, lettuce and tomatoes and/or salsa. Combine sour cream and lime juice and pour on top of nachos. Top with cilantro. Other toppings I love: avocado, chipotle hot sauce, roasted peppers and more cheese!