Coat both sides of the chicken with taco seasoning and place on a parchment paper-lined sheet pan. Drizzle with a little oil. Bake for 15-20 minutes or until chicken reads 165 degrees on an instant-read thermometer. Cool slightly and slice.
While chicken bakes, gather and slice or chop the toppings as needed.
Assemble the taco bowls. Layer Doritos with chicken and all of the fixings.
Ground chicken can be substituted for the chicken breasts. Cook the ground chicken thoroughly, crumbling it as it cooks. Season with one packet of taco seasoning according to package directions.
To prep the chicken ahead of time: Bake and cool the chicken. Then store it in an air-tight container in the refrigerator for 3-4 days.