Conor McGregor just posted a message to Nate Diaz -- setting the groundwork for a 3RD FIGHT ... and telling Nate, "I'll be prepared."
The Irish superstar noted that Tuesday marks the 3-year anniversary of McGregor vs. Diaz II -- a fight Conor won by split decision at UFC 202 in 2016.
"3 years to the day myself and this Mexican animal went to war," Conor said.
Then he dropped this bomb -- "I’ll be prepared for it when we go again. If we go again."
"If not, respect always.