
Irish nachos are everything you love about nachos with one major bonus: your favorite toppings are loaded onto a pile of crispy, golden potatoes.
Preheat the oven to 425°. Wash the potatoes and pat dry thoroughly. Slice the potatoes into 1/4-inch-thick rounds. In a large bowl, stir together the potatoes, olive oil, pepper, and garlic powder until well combined.
Spray two rimmed baking sheets with nonstick cooking spray. Divide the potatoes equally between pans and arrange them in an even layer. Bake for 20 minutes then remove the pans from the oven. Flip the potatoes, rotate the pans, and return to oven. Bake until the potatoes are golden brown, about 10 to 15 minutes more.
Remove the potatoes from oven and sprinkle evenly with the salt. Let cool 5 minutes. Combine the potatoes on one pan and sprinkle with the bacon and shredded cheese. Return the pan to oven and bake until cheese is melted, about 5 minutes more. Sprinkle with the quick-pickled onions and green onions; top with salsa and sour cream.
To make the quick-pickled onions (optional): Combine the onion, vinegar, 1/2 cup water, sugar, and salt in a small microwave-safe bowl or measuring cup. Microwave on high for 3 minutes. Let cool 15 minutes.