Yes, the cook time on a pressure cooker chuck roast recipe will be appreciably different if you're cooking cut chunks instead of a whole roast. When using a pressure cooker, the cook time is influenced by the thickness and size of the meat. Chunks of chuck roast will have a significantly smaller volume compared to a whole roast, which means they will cook much faster.
When cooking chuck roast chunks in a pressure cooker, the cook time can be reduced to achieve tender and fully cooked meat. The exact time will depend on the size of the chunks, but it will generally be shorter than the time required for a whole roast.
Keep in mind that pressure cooking times are based on achieving a specific level of tenderness, so it's essential to adjust the cook time accordingly to avoid overcooking the meat. Always follow the specific recipe instructions or guidelines for cooking chuck roast chunks in a pressure cooker to achieve the best results. If you're unsure, you can use a meat thermometer to check the internal temperature of the chunks to ensure they are properly cooked.