Put onion and hamburger meat in large skillet and cook on med heat. Stir. Cook until done. Then drain and add to mixture in 9-13 baking dish.
While onion and humbrger meat is cooking. Use a 9-13 baking dish. And add the following ingredents into dish. Shredded cheese,cream of celery suop, can cheddar cheese soup, cream of mushroom soup. Add drained can of mushrooms and drained can of peas and carrots. Mix very well.
When hamburger and onions has been cooked, drain and add to mixture. Stir very well.
Open bag of tater tots and put on top of mixture. Spreading out evenly. Put into oven and cook as directed on package. 20-25 min. Then serve with salad of your choice.