- Position rack in center of oven and preheat the oven to 400Â°F.
- In a 9 by 13-inch baking dish, spread half of the tortilla chips in one even layer and top with half of each cheese.
- Repeat with another layer of chips and the remaining cheeses.
- Bake until the cheese is melted and chips are crispy, about 8 to 10 minutes.
- Using oven mitts or pot holders, remove the nachos from the oven, sprinkle with the scallions, and allow to cool slightly, about 2 minutes.
- Serve either straight from the baking dish or divide among serving plates and serve with Salsa, Guacamole, and sour cream spooned over the top if desired.