Add the water and sprinkle roast with taco seasoning.
Place the lid on, making sure that the pressure valve is closed. Set to manual mode (high pressure) for 120 minutes if frozen, or 90 minutes if not.
Once the meat is done cooking, let it sit for about 15 minutes for natural pressure release.
My frozen-solid roast was done perfectly in 120 minutes of cook time. Note that it also took about 15 minutes to get up to pressure and start the countdown, plus it took about 15 or 20 minutes for the pressure to release naturally. If you have excess liquid at the bottom of the pot when you open the lid, just hit the sauté button and let it simmer off, stirring every couple of minutes. It won't take long.Serve on your favourite tortillas with your favourite toppings, and enjoy your super-easy shredded beef tacos from scratch. Feel like a boss - you deserve it.