In a mixing bowl, combine the tomatoes, garlic, onions and half of the cilantro. Season with salt and set aside.
Spread the Baked Tortilla Chips on a baking sheet and top with the black beans, pinto beans, olives, Cheddar and pepper Jack. Cook until the cheese melts, about 5 minutes.
While the nachos are cooking, slice each lime into 6 wedges. Squeeze 2 of the wedges into the yogurt, season with a pinch of salt and stir. Reserve the remaining wedges for serving.
While the chips are still hot, scatter the tomato mixture and avocados on top, then drizzle on the yogurt. Top with the remaining chopped cilantro. Serve with lime wedges.
Baked Tortilla Chips:
Preheat the oven to 350 degrees F.
Brush both sides of the tortillas with the oil. Stack the tortillas and cut the pile into sixths to make chips. Spread the chips out in a single layer on 2 large baking sheets and season with salt. Bake until golden brown and crisp, rotating the baking sheets once, 12 to 15 minutes.