Warm the milk with the cream cheese cubes in a saucepan over low heat, whisking as the cheese softens.
Whisk until the cream cheese melts fully into the warm milk into a smooth, pale, creamy base.
Take the saucepan OFF the heat and stir the cheddar in batches until smooth and glossy.
Lay a single layer of chips on a parchment-lined pan, sprinkle shredded cheese over them, and scatter the black beans over the chips.
Bake at 400°F for 5-10 minutes until the cheese is fully melted and bubbling and the chip edges are golden.
Pour the warm queso in a thick stream over the hot nachos so it flows between the chips.
Scatter diced tomato, jalapeño rings, red onion, and cilantro over the queso-covered nachos and serve right away.