NBC Sports announced that it will produce its own Las Vegas-based poker tournament -- a move that could be a prelude toward landing the World Series of Poker on network television. NBC will film the National Heads-Up Poker Championship, a showdown between 64 players at the Golden Nugget in early March, just the latest in a series of new television programs aimed at capitalizing on poker's growing popularity. The event, which features a $1.5 million purse …Unlike other televised poker events, the format will be head-to-head competition with a single elimination. Players will pay a $20,000 buy-in and play no-limit Texas Hold 'em. The overall winner will receive $500,000.