Prepare all of the ingredients. Preheat oven to 425deg
In a bowl, combine tomatoes, onion, garlic, lime juice and cumin. Set aside until ready to build nachos.
In a large saute pan over medium-high heat, add ground beef and seasonings. Cook and crumble until no longer pink.
Cover 2 large baking sheets with foil. Start with a single layer of chips, then sprinkle each tray with half of the ground beef, then half of the pinto beans, then half of the cheese. Place in oven and bake for 20 minutes.
To build an individual plate of nachos - put roughly a quarter of one tray on a plate. Top with fresh salsa, the sour cream, taco sauce, scallions and jalapenos (if desired).