Place the meat in a zippered bag or covered container.
Combine remaining ingredients and pour over meat, being sure that all meat is covered.
Allow to marinate 3o minutes or more. You can skip this step if you don't have time.
Cooking method 1: Stovetop: Sautee onions for a few minutes in oil. Add pork and marinade in medium pot and add enough water to just cover the pork. Bring to a boil on high heat and then reduce to a simmer, uncovered. Allow to simmer until the liquid evaporates (about 2 hours) and then continue to cook a little longer to allow the meat to caramelize. Carefully turn the meat to allow it to brown on all sides. Shred with forks if you want smaller pieces.
Cooking method 2: Instant Pot: Sautee onions for a few minutes in oil, in the Instant Pot. Add pork and marinade to Instant Pot and add just enough water to just cover the pork. Seal lid and set to manual pressure high for 35 minutes. Allow to naturally depressurize for about 10 minutes and then manually release the rest of the pressure. Remove the lid and change setting to sautee. Allow to boil until liquid has mostly evaporated, but stir occasionally so it doesn't burn. Shred with forks if you want smaller pieces. Spread meat onto a baking sheet and place under broiler for 5 minutes or so until slightly crispy.