The dealer button represents the person who will be last to act on all subsequent rounds. This means you have more information to work with. Since poker is a game of partial information, the more you have the better off you are. The dealer button is a huge advantage.

"Nuts on the Flop"... Well, the flop is the first 3 community cards the dealer puts out. The "Nuts" is a term for the best hand. To say you had the nuts on the flop, would mean you had an unbeatable hand at that point. For example, if you hold Ace and King, and the Flop is Q J 10 of all different suits, you have flopped "The Nuts"