James Harden Contract -- Nike's Out ... Khloe Kardashian Called It!

James Harden is dead to Nike -- the Swoosh is backing out of the running to land a new contract with Khloe Kardashian's NBA superstar BF ... TMZ Sports has learned.

Sources connected to Nike tell us the company has decided it won't try to top the $200 million deal Adidas offered Harden last week. As we've reported ... Nike had concerns about sinking that much dough into just ONE player, when it has several other superstars to sign.

Harden has yet to officially accept Adidas' 13-year deal, but the writing is on the wall ... or on Khloe's back. She was sporting Adidas gear at his Drew League game this weekend.

Not to mention ... his teammate Dwight Howard, and potential future bro-in-law Kanye West are already down with 'Das.