Preheat the oven by setting it to broil on high (about 350°F is indicated in the original; follow your oven's broil setting and monitor closely).
Heat the olive oil in a large skillet over medium-high heat.
Add the ground turkey and taco seasoning to the hot skillet and cook, breaking it up with a spatula, until no pink remains, about 7–8 minutes.
When the turkey is nearly done (about 1 minute remaining), stir in the drained and rinsed black beans and warm through.
Line a large baking sheet with foil and spread the tortilla chips in an even layer.
Top the chips with the hot turkey and black bean mixture, then sprinkle the shredded Mexican blend cheese evenly over the top.
Place the baking sheet under the broiler and heat until the cheese melts and becomes bubbly, about 4–6 minutes—watch closely to avoid burning.
While the nachos broil, make the creamy jalapeño sauce: combine Greek yogurt, avocado, jalapeño (stem and seeds removed), fresh dill, fresh chives, garlic, lime juice, and salt in a food processor or blender and blend until smooth.
Remove the nachos from the oven. Top with shredded lettuce and spoon the salsa over the nachos.
Drizzle the creamy jalapeño sauce over the nachos or serve it on the side, then serve immediately.