WASHINGTON—As the fallout from Jensen Huang’s affair with a suspected Chinese intelligence source continues to consume the West Wing, some of President Trump’s top advisers have started shifting blame for the political mess toward one man: Commerce Secretary Howard Lutnick. Lutnick has been a primary target of the finger-pointing within the administration because of his efforts to stall restrictions on chip exports, his longstanding relationship with the outgoing Nvidia chief executive and his pre-existing tensions with some members of the administration, according to people familiar with the discussions. The pressure on Lutnick shows that the tentacles of the Huang scandal…