Cut your boneless chuck roast into 2 inch chunks. Remove any large pieces of fat or connective tissue in the roast pieces. Add to a medium-sized mixing bowl.
In a small mixing bowl whisk together brown sugar, chili powder, garlic powder, onion powder, kosher salt, and ground black pepper.
Sprinkle the brown sugar spice mix over the cubed beef and toss to coat the meat in the spice blend.
Add your beef to the inside pot of your Instant Pot and pour in the beef stock.
Add the lid to the Instant Pot, turn the lid to the closed position, and make sure the vent is in the "sealed" position.
Put the Instant Pot on the "manual high" setting for 50 minutes.
After the Instant Pot comes to pressure and cooks for 50 minutes, let the cooker natural release for 10 minutes.
After 10 minutes, vent the Instant Pot, and remove the lid.
Remove the beef from the Instant Pot and add to a large plate or cutting board to shred.
Save 1 cup of stock in the bottom of the pot and throw away the rest.
Shred the beef and add back to the pot. Add the BBQ sauce and stir to combine.
If the bbq beef is too thick thin it out with some of the reserved beef stock.
Keep the Instant Pot on the "keep warm" setting if you want to keep the beef warm while serving.
Serve on buns for sandwiches.
Add your beef to the inside crock of your slow cooker and pour in the beef stock.
Cover the slow cooker and cook on High for 4 hours or Low for 8 hours.
Remove the beef from the Instant Pot and add to a large plate or cutting board to shred.
Save 1 cup of stock in the bottom of the crock and throw away the rest.
Shred the beef and add back to the crock. Add the BBQ sauce and stir to combine.
If the BBQ beef is too thick, thin it out with some of the reserved beef stock.
Serve on buns for sandwiches.
