Preheat the oven to 325°F. Grease a Dutch oven or deep 9x13-inch baking dish with nonstick cooking spray.
Dry the chuck roast well with paper towels and place directly in the prepared baking dish.
In a small mixing bowl, stir together condensed cream of mushroom soup and dry onion soup mix until well combined.
Spread soup mixture all over the top and sides of the chuck roast, ensuring it is completely smothered.
Seal the baking dish tightly with a heavy-duty lid, or crimp a double layer of aluminum foil tightly around the rim to ensure the steam is trapped inside.
Bake covered for about 3 hours, or until the beef easily falls apart when tested with a fork.
Transfer to a cutting board and let rest for 10 minutes. Slice or shred as desired. Serve warm, spooning gravy on top as you go.
*Nutritional information is a calculated guesstimate. Please note that this can change with different brands and modifications you may make to the recipe. For the most accurate information, use a nutritional calculator with the exact brands and measurements you're using with each recipe.