(Reuters) - Slot machine makers International Game Technology and Bally Technologies Inc said they have been granted online gaming licenses in Nevada, paving the way for the companies to grab market share when U.S. internet gambling laws are relaxed.The U.S. Justice Department last year declared that only online betting on sporting contests is unlawful, which experts say will allow states to unilaterally legalize some forms of online gambling in 2012, from lotteries to poker.IGT and Bally said in separate statements that the licenses would allow them to partner with Nevada's casinos to provide online poker and other interactive games through their machines.Consulting firm H2 Gambling Capital has forecast that Internet betting operators will win more than $35 billion globally from gamblers this year. It estimates that for online poker, just 37 percent of an estimated 2011 total of nearly $5 billion took place within regulated markets.(Reporting by Jochelle Mendonca in Bangalore; Editing by Richard Pullin)