Preheat the oven to 350F and position the top oven rack in the middle of the oven. Line a 9x13 baking dish with parchment paper.
In a medium bowl, combine the rotisserie chicken and salsa, coating the shredded chicken well. If using chopped chicken breasts or thighs, chop the chicken into small pieces first.
Assemble the nachos:
Layer half of the tortilla chips on the parchment paper. Top this first layer with half the cheese. Make a second layer of chips over the first layer and top with more cheese, diced tomatoes, red onion, black olives, and shredded chicken. You can top the chicken with cheese or layer it; this is up to you.
Melt 'em
Place the layered nacho tray in the preheated oven and bake it for 10 to 12 minutes until the cheese looks melty and the pulled chicken is warm. Remove the tray from the oven.
Serve:
Serve the nachos in the same 9x13 tray or gently lift the parchment paper and slide a platter big enough to hold the nachos underneath.
Top the loaded rotisserie chicken nachos with any fresh toppings, like guacamole and sour cream.