Cook the bacon until it's brown and crisp. Drain on paper towels and chop. Set aside. (Note 1)
Add the shredded chicken to a bowl. Add the ranch dressing and toss to combine. Set aside.
On a quarter sheet pan, arrange an even layer of the Doritos. Top with half of the chicken, bacon, onions, and cheese. Repeat with a second layer.
Bake the nachos for 10-12 minutes until the cheese is melted. After 10 minutes, keep an eye on them, since the Doritos can burn more easily than traditional tortilla chips.
Garnish with ranch dressing, guacamole, pickled jalapenos, and cilantro. Serve immediately.
Notes
To cook the bacon in the oven, arrange the bacon on a foil-lined sheet pan. Bake for 10-15 minutes at 400 degrees until brown and crisp.
Shred your own cheese. Freshly shredded cheese melts so much better than pre-shredded cheese which has additives to prevent clumping.
Build the nachos in layers so that all of the chips are equally coated with cheese and other toppings.
Build the nachos on a sheet pan for ease of heating and clean-up. Use a half-sheet pan for larger gatherings or a quarter sheet pan for small batches.
Garnish the nachos with various toppings or set out the toppings for a "top-your-own-nachos" bar.