Dice the red and green bell peppers and the red onion.
Sauté the peppers and onion in the olive oil until just starting to soften, keeping a little bite.
Stir in the black beans, corn, cumin, and chili powder and toss until colorful, glossy, and fragrant.
Lay a single layer of chips on a parchment-lined pan and sprinkle the first cheese over them.
Spoon the colorful vegetable filling over the cheese-topped chips, edge to edge.
Cover the vegetable filling with the remaining shredded cheese in a thick layer.
Bake at 400°F for 5–10 minutes until the cheese is fully melted and bubbling and the chip edges are golden.
Scatter diced tomato, avocado, cilantro, and jalapeño rings over the hot vegetarian nachos and serve right away.