Cut the chuck roast into even 1 inch cubes. Remove as much of the fat as possible.
Pour spice mix onto large cubes of beef and make sure beef is evenly coated. (You can use a large baking dish)
Heat 2 TBSP avocado oil in a large pot on the stove over medium heat. Sear the beef cubes until all sides are browned. Make sure to sear in groups so as to not overcrowd the pot. If you notice the bottom of the pot gets dry, add some more oil. Once all pieces are browned, place beef on a plate or in a bowl to the side.
In the same pot (keep the browned bits), add diced onion and cook for 2-3 minutes. You can add oil if the pot is a bit dry. Turn down the heat to medium.
Stir in the minced garlic.
Pour in orange juice and lime juice and scrape the browned bits of the pan while mixing together.
Add the enchilada sauce and water to the pot.
Add the cooked beef meat and all of the juices back into the pot. Stir to make sure it is completely mixed together.
Bring heat back up to medium-high until liquid is boiling.
Place the lid on the pot and turn down the heat to a low simmer.
Simmer for 1 hour and 15 minutes. Stir the liquid and meat around 1-hour into the simmer.
After simmering for 1 hour and 15 minutes, your meat should be super tender. If you press the meat with a wooden spoon, it should break apart into pieces.
While keeping the sauce simmering, remove the beef cubes using tongs and into a prep bowl. Take two forks and shred the beef chunks. If there are any pieces of fat that didn’t cook off, you can remove it from the beef.
Raise heat to medium-high, add the shredded beef back to the pot. Cook for 5-10 minutes, letting the sauce thicken up and the beef soak up the sauces.