Preheat oven to 375 degrees F. Arrange tortilla chips on a large baking sheet covered with parchment paper. Set aside.
Place the cooked, shredded chicken in a large bowl. Sprinkle with garlic powder, onion powder, and season with salt and pepper. Add as much barbecue sauce to the chicken as desired. Stir well to combine everything.
Top the tortilla chips evenly with the shredded barbecue chicken. Top chicken evenly with both shredded cheeses. Top cheese evenly with the diced red onion.
Bake for 12 minutes or until cheese is melted and bubbly. Carefully remove from oven. Top nachos with chopped cilantro, tomato, sliced jalapeno, or whatever you desire. Serve warm and enjoy!