Do you just say stuff at random without fact checking?
Anyone can play any clubs at any time, regardless of sponsorship. Nike has no control over what clubs people use, nor are they able to stop anyone from using their clubs should they want to.
Nike is a good brand considering they haven't been on the market as long, but they are no better than any of the other major manufacturers. The only reason Tiger plays Nike is because they paid him the big bucks (40 million was the original endorsement deal back in 1996, probably upwards of 100 million today). He's also under contract.
Also, when you consider how deep the Woods-Nike relationship is and the fact that Nike is plastered all over his own game, I doubt they would even be interested. They have all the endorsements they need right now.