Place the pork into an electric pressure cooker. Add the water, onion, and seasonings in there too. Program to the high pressure setting for 50 minutes. Once the cooking cycle is completed, allow the pressure to naturally release all the way, will take up to 20 min.
Remove meat from the pot and shred it with two forks. (Reserve some of the strained broth if you are making homemade masa and/or tamale sauce) Toss shredded pork with tamale sauce to keep it moist and you're ready to add into your masa dough.