Preheat oven to 400°F (205°C). Spread oil in a broiler pan or cookie sheet.

Peel sweet potatoes and slice thinly. I use my vegetable spiralizer; you can also use a chef’s knife or mandolin.

Toss sliced sweet potatoes in the oiled pan and shake or stir to get a little oil on each piece. Spread sweet potatoes in an even layer and season with cumin, oregano, chili powder, and salt. Bake in preheated oven 20-25 minutes, until mostly done.

Meanwhile, drain the beans, grate the cheese, and chop the tomatoes.

Sprinkle beans and cheese over the baked sweet potatoes and pop the tray back in the oven. Switch oven to broiler and cook until cheese is bubbly, about 5 minutes.

Remove from oven, scatter chopped tomatoes, olives, cilantro, and chives over the top of the nachos.

Serve immediately with sour cream, if desired. Refrigerate any leftovers in a covered container and enjoy within 3 days.