NFL's Chandler Jones -- Calls Out Jon Jones ... He's Scared to Fight Me!!!

New England Patriots star Chandler Jones is now TROLLING his UFC star brother -- claiming Jon Jones is SCARED to fight him ... and is running and hiding like a coward.

We broke the story ... Chandler says he's 100% down to fight his big bro, who happens to be the reigning UFC light heavyweight champ, and wants to set up a match for charity.

But in NYC this weekend, while waiting to hail a cab with teammate Rob Gronkowski, Chandler called out his brother right on the street ... literally ... he dialed Jon up on his cell.

As we previously reported, Chandler is dead serious about making the fight happen ... as long as he gets approval from the Pats.

Stay tuned ...