In a large skillet over medium heat, add the lean ground beef. Cook until browned, breaking it apart with a spatula as it cooks. This should take about 5-7 minutes. Drain any excess fat to keep the dish healthier.
Once the beef is cooked, stir in the salsa, mixing well to ensure the beef is evenly coated. Allow the mixture to simmer for an additional 2-3 minutes to let the flavors meld together.
While the beef is simmering, wash the mini bell peppers and slice them in half lengthwise. Remove the seeds and membranes to create little boats for your nacho toppings.
Preheat your oven to 350°F (177°C). On a baking sheet, arrange the halved mini bell peppers cut side up. Spoon a generous amount of the seasoned ground beef mixture into each pepper. Top with shredded cheese, ensuring every pepper gets a good amount.
Place the baking sheet in the preheated oven and bake for about 10-12 minutes, or until the cheese is melted and bubbly. Keep an eye on them to avoid overcooking.
Once the nachos are out of the oven, garnish them with diced tomatoes, green onions, and avocado. Sprinkle freshly chopped cilantro on top for a burst of flavor.
Serve your Mexican Mini Bell Pepper Nachos warm, and watch them disappear! They make for a perfect appetizer or light meal that everyone will love.