Cut the chuck roast into 2 inches pieces. Set aside.
Add the salsa verde, onion, chipotle peppers, garlic, cumin, salt, and pepper to a food processor or blender and process until smooth.
Turn the Instant Pot to saute and wait for the pan to heat. Once hot, add the oil and let heat.
When the oil is hot, add the chuck roast and sear, stirring occasionally to brown all sides.
Add the salsa verde mixture and the beef broth to the Instant Pot and turn to manual pressure.
Close the lid and set to sealing.
Cook on high pressure for 35 minutes. Let pressure release naturally, about 20 minutes.
Remove the meat from the Instant Pot and shred with forks.
Sprinkle with cilantro before serving.
To make this in a slow cooker, sear the beef on the stove in a heavy bottomed pot. Add to a slow cooker along with the sauce as directed above. Cook on high for 5 hours or low for 9 hours, until the meat is easily shred with a fork.