01 - Preheat oven to 400°F (200°C) and line a large baking sheet with parchment paper.
02 - In a medium bowl, gently toss together mango, pineapple, red onion, jalapeño, cilantro, lime juice, and salt until fully mixed. Set aside.
03 - Arrange tortilla chips in a single, even layer on the lined baking sheet.
04 - Evenly distribute shredded chicken over the chips. Scatter the shredded Monterey Jack cheese across the chicken and chips.
05 - Place the baking sheet in the oven and bake for 10 to 12 minutes, or until cheese is fully melted and bubbling.
06 - Remove nachos from the oven and spoon the prepared mango pineapple salsa evenly across the top.
07 - Finish with crumbled queso fresco and diced avocado. Optionally spoon dollops of sour cream and sprinkle sliced green onions.
08 - Serve immediately while nachos are warm for best texture and flavor.