Coat the inside of a 9 x 13 casserole dish with nonstick spray, or grease with shortening.
Flatten 2 lb of the ground chuck (reserving the other 1 lb for later) across the bottom of the casserole dish.
When the oven is up to temperature, bake the ground chuck in the dish for about 20 minutes or until it’s brown. You’ll notice the ground chuck will have shrunk quite a bit.
Remove the meat from the oven and drain the grease into a bowl. Position the cooked beef into the corner of the pan and, using the remaining 1 lb of beef, fill in the rest of the bottom of the casserole dish.
Bake for another 25 minutes or so until the beef is fully cooked. Remove from the oven and drain off the rest of the grease from the dish.
Spoon the soup onto the cooked ground chuck and spread it evenly. Layer the frozen vegetables evenly across the layer of soup, topping the vegetables with the tater tots.
Place the dish back into the oven for another 15 – 20 minutes until the vegetables are hot but still crisp, and the tater tots are golden brown.