Guam Temporary Workforce Act This bill directs the Department of Homeland Security to approve a completed employer petition for a nonimmigrant H-2B visa alien (temporary nonagricultural services) on Guam as long as the petition includes an approved temporary labor certification issued by the Governor of Guam within the last 365 days. Such certification may only be invalidated if a court of law determines that the certification request involved fraud, willful misrepresentation, or gross misconduct.