In a mixing bowl, combine brown sugar, soy sauce, toasted sesame oil, grated ginger, and red pepper flakes, whisking until smooth. Heat a large skillet over medium-high heat and add vegetable oil. Sauté minced garlic for about 30 seconds until fragrant, then add ground beef, cooking until browned and crumbled, about 5-7 minutes. Drain excess fat and stir in the prepared sauce, simmering for an additional 2 minutes until heated through and slightly thickened.

In the same skillet, add a drizzle of vegetable oil over medium heat. Toss in the chopped kimchi, sesame oil, and sugar, allowing it to cook for 3-5 minutes. Stir occasionally until the kimchi turns slightly caramelized and fragrant.

In a small bowl, mix together mayonnaise and Sriracha, adjusting the amount of Sriracha to suit your heat preference. Stir until well combined and creamy.

Preheat your oven to 400°F (200°C). Prepare a baking sheet by lining it with nonstick spray. Begin by spreading a single layer of sturdy tortilla chips evenly across the sheet. Top the chips with the cooked Korean beef mixture and a blend of shredded cheddar and Monterey Jack cheese.

Place the assembled nachos in the preheated oven and bake for 5-6 minutes. Keep an eye on them as they cook; you'll know they’re ready when the cheese is bubbly and melted, and the chips are hot.

Once baked, remove the nachos from the oven and immediately top them with the caramelized kimchi. Drizzle generously with the Sriracha mayo, and finish with fresh cilantro and sesame seeds.