Declaring the NLRB unconstitutional works both ways.
Corporations have stacked the deck when it comes to the current rules and regulations surrounding Unions. Disbanding the NLRB gives corporations even more power, but Unions will also be unchained. The government is going to have a lot less say in how strikes are executed and how unions are formed. States that outlaw or attempt to clamp down on labor are going to see much more unionized political activism than they see now.