The nut found within a prickly shell is commonly known as a "chestnut." Chestnuts are encased in a spiky husk, which splits open when the nuts are ripe. They are distinct from other nuts, such as acorns or hazelnuts, which have different outer coverings.
This description matches that of a chestnut, which is a nut enclosed in a spiky, green outer husk. The reddish-brown nut is edible and commonly used in cooking and baking. Be cautious when handling the prickly outer covering to avoid injury.
Possibly an American chestnut.
Tom Thumb Cactus is a prickly plant.
Cactus
Rambutan fruit, Lychee fruit, Rose Hips
The nut with the hardest shell is the macadamia nut. It is difficult to crack because the edible part is stuck to the inside of the shell.
cacti
The Thistle.
cactus
Burr
Cactus
The Briar Patch