I'd call a chicken pot pie a pie.
"Hotdish" is a regional name for a casserole. Which is the name of both the vessel and its contents.
I'd call it a chicken pot pie a savoury pie. Regional = MN, WI, ND, maybe part of northern IA and maybe a corner of SD, depends on the ethnic background of the people who settled in the area. I don't recall that any of the vessels were called hotdishes, just the contents, when I lived in MN. There was also a cultural/social difference re: hotdish and casserole. A hotdish was s/thing you served to family but a casserole was s/thing you could serve to company because it had more expensive ingredients and was more "elegant." Wish I could afford to go back to university and get funding to research this and write a thesis on it!
For example, that standby of noodles, cream of XX soup, peas, celery, a can of tuna, S&P is a hotdish, topped, of course, with crushed potato chips, cooked in the oven at around 350 for about 35-40 minutes and that is tuna hotdish. I don't know when we would've called it a casserole. But, when we would take wild rice, ham/shrimp/chicken, broccoli, cream of mushroom soup or a white sauce, add some mushrooms, celery, onion, frozen peas, put it all together and bake it in the oven for about 45 minutes at 350 in a dish that could be brought to the table, (and served to company or brought to a church supper or other potluck functions) that would be wild rice casserole. Note: no potato chips to make a crust.
A stew was something that had to cook low and slow, didn't include pasta (instead it would have potatoes, carrots, rutabaga, turnips--fall/winter veggies) or was made in the pressure cooker or started on the stove and finished in the oven. The meat (usually beef) came from the front of the animal--a bit tougher, needed the longer cooking time. FWIW--Kebab meat comes from the back end--not as muscular and can be cooked at higher temps and faster.