Buckeye Nuts are only edible if they are cooked or roasted first and removed from the shells.
Ohio Buckeye Nuts though are toxic and not edible.
Other Buckeye Nuts can be eaten as long as you roasted them first and removed the Buckeye Nuts from the shells.
Buckeye Nuts are toxic in the uncooked state but once you roast them they become edible and non toxic.
Native Americans would roast, peel, and mash the buckeye nuts into a fairly nutritional paste that they would eat.
So that's a way you could eat the Buckeye nuts for the nutrition.