Preheat Oven: Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper or aluminum foil for easy cleanup.
Cook the Beef: In a large skillet, heat olive oil over medium heat. Add diced onion and minced garlic, and sauté until softened, about 3-4 minutes. Add grass-fed ground beef and cook until browned, breaking it apart with a spatula as it cooks. Drain excess fat if necessary. Stir in taco seasoning mix until well combined. Remove from heat.
Assemble the Nachos: Arrange the tortilla chips in a single layer on the prepared baking sheet. Spoon the cooked beef mixture evenly over the chips. Scatter black beans and corn kernels over the beef.
Add Cheese: Sprinkle shredded cheddar cheese and shredded Monterey Jack cheese evenly over the beef, beans, and corn.
Bake: Transfer the baking sheet to the preheated oven and bake for 8-10 minutes, or until the cheese is melted and bubbly.
Serve: Remove from the oven and let cool slightly. Garnish the nachos with your favorite toppings such as sliced jalapeños, diced tomatoes, sliced black olives, chopped cilantro, sour cream, guacamole, and salsa. Serve hot and enjoy your delicious grass-fed beef nachos!