Thursday is the first time Arizonians can bet online — betting on everything from who will win to the minute details of the game. The state joins 22 others and the District of Columbia where sports betting is legal. In the three years since the Supreme Court sided with New Jersey's challenge to Nevada's monopoly on sports betting, mericans have wagered more than $65 billion on sports, according Legal Sports Report. New Jersey has since surpassed Nevada as the state with the most sports bets monthly.