I named my gamertag after a NBA player i like. Is this copyright infringment?
No. I could not be copyright infringement, as names and titles cannot be copyrighted.
They can be trademarked. But even there, naming your pet, for example, “Pepsi” ™ is unlikely to be rise to the level of infringement of the trademark. All the more so in the case you describe.
Think of it this way: Is “the” Michael Jordan the only Michael Jordan in the world?