Dallas Mavericks fans clearly still loathe Nico Harrison for trading away Luka Doncic … one actually yelled right in the GM’s face on Monday, “Fire Nico!” — repeatedly!

The scene unfolded just before the Mavs’ tilt with the Brooklyn Nets at American Airlines Center in Dallas … as Harrison — who jettisoned Doncic to the Lakers back on Feb. 1 — was saying hi to some people who had shown up for the game a bit early.

The 52-year-old shook one person’s hand, and then as he turned to go back to Dallas’ locker room area — a Mavs backer yelled that he should be canned.

But, according to one Reddit user who claimed to have seen the whole incident, stadium security confronted the fan a short time later. It’s not clear if the guy — who was wearing a No. 77 Doncic Mavericks jersey — was removed from the venue over the altercation, though the officials didn’t seem pleased with him, to say the least.

Harrison’s Mavs, meanwhile, continued to struggle without Doncic — they lost to Brooklyn, 113-109. They’re now 37-39 in the year.