Pat the chuck roast dry and season on both sides with salt, pepper, and garlic powder.

In the insert of a multicooker or in a large skillet over medium high heat, brown the chuck roast on both sides, approximately 4 minutes per side. Set aside.

Pour the beef stock into a 2 cup measuring cup. Add the vinegar and the Worcestershire sauce and stir together.

Add the potatoes, carrots and mushrooms in the bottom of the slow cooker insert. Top with 1 sprig each of rosemary and thyme, and sprinkle half of onion soup packet over top. Place with browned chuck roast. 

Pour the beef stock mixture and wine over top of the chuck roast and vegetables. Top with remaining herb sprigs and soup mix. 

Cover and cook on LOW for 8-10 hours. 

Remove pot roast and vegetables to serving platter or cutting board. Cover with foil to keep warm. 

Pour juices into saucepan and whisk in brown gravy packet. Simmer until thickened. If you are using a multi cooker, you can do this in the slow cooker pot/insert on the "Sauté" setting.

Serve hot.