Add all ingredients except the chuck roast to a high-powered blender or food processor and blend until a thick sauce has formed. Set aside.
Turn the Instant Pot on to Sauté on high for 15 minutes and add some avocado oil.
While the oil is heating, cube the Chuck Roast into about 1-inch pieces.
Begin adding the cubed roast to the Instant Pot searing each side. Once the meat is seared on the outside, turn the Instant Pot off.
Pour the sauce from the blender over the cubed beef and give it a good stir to cover it entirely.
Place the lid on the Instant Pot, and set it to pressure cook, high, for 60 minutes.
Once the cooking is done, manually release the pressure and carefully shred the beef using forks or shredders.
Place the lid back on the Instant Pot, set it to keep warm on high, and serve when ready.