Ben Crump -- the attorney for Nolan Wells' family -- is set to speak publicly for the first time since a grand jury decided not to pursue criminal charges in his death ... and TMZ is streaming live.

The press conference will begin in just a few minutes ... and it's a good bet the outspoken attorney plans to dive into the lack of indictments, despite his repeated insistence since early July that Nolan's death involved foul play.

As we reported ... the grand jury -- which was impaneled in April and featured 23 members -- found that the "position of, the condition of, time of discovery, and location of Mr. Wells' body is consistent with drowning."

Shortly after the grand jury decision, District Attorney Angel Myers McIlrath said in a video there is "absolutely no evidence" to support the claim that Nolan's death was "racially motivated."

Edward Andrew Paltzik, the attorney for Nolan's friends who went with him to Horn Island on the day he disappeared, told us ... "We said it all along: Warren Hudson, Jax Pitalo, and Morgan Seymour were always completely innocent. There was never any doubt. They are terrific people."

Crump released his own written statement after the finding ... claiming "the State of Mississippi is attempting to close the chapter on Nolan Wells' death without getting to the truth."