Rub the two chicken breasts with the chili powder, cumin, garlic powder, paprika, and salt until evenly coated.
Sear the seasoned breasts in a hot oiled skillet until golden-brown on both sides.
Check the thickest part with an instant-read thermometer — it must read 165°F.
Shred the cooked chicken with two forks while it is still warm.
Squeeze fresh lime juice over the shredded chicken and toss to coat.
Lay a single layer of chips on a parchment-lined pan and sprinkle the first cheese over them.
Scatter the shredded chicken and black beans over the cheese-topped chips.
Cover with the remaining shredded cheese in a thick layer.
Bake at 400°F for 5-10 minutes until the cheese is fully melted and bubbling and the chip edges are golden.
Scatter diced tomato, red onion, avocado, and cilantro over the hot chicken nachos and serve right away.