When you hold the nuts in poker, also known as the stone-cold nuts, the mortal nuts, or best of all the brass Brazilians, your poker hand is the best possible hand.
In the context of a specific hand of poker the nuts could be as low as three of a kind (in hold'em). For instance if the board reads 2s-5h-8c-Jd-Kh then the highest possible hand would be pocket Kings for a set of Kings. In this case pocket cowboys would qualify as the nuts!