Pre-heat oven to 200C / 390F.
Wash and peel sweet potatoes, and slice into 0.5cm (0.2”) thick rounds using a knife or mandolin.
Lay sweet potato slices out on a lined baking sheet and bake in oven for 15 minutes until beginning to brown and crisp.
In a fry pan over medium heat, warm the oil. Add the onion, bell pepper, and zucchini and cook until just soft (5-8 minutes).
Add the minced meat into the frying pan and cook until fully browned, (about 10 minutes). Season with salt and pepper.
Remove the sweet potato from the oven. Using the baking sheet from the sweet potatoes, overlap the cooked chips to form your nacho base.
Scatter meat and vegetable mixture across the sweet potato base. Top with diced tomatoes and shredded cheese.
Return to the oven and bake until cheese ismelted and beginning to turn golden;around 10 minutes.
Top with any of the optional garnishes, and enjoy!