Google stepped closer to acquiring Nortel’s portfolio of 6,000 telecommunications, wireless and Internet patents on Monday as courts in the U.S. and Canada approved the web search giant’s “stalking horse” offer of $900 million for those patents. Announced on April 4, Google’s offer effectively constitutes the opening bid in an auction that will be decided at a joint hearing of the U.S. and Canadian courts on June 30. The auction also opens the latest chapter in the ongoing bankruptcy process for Nortel.