Nicki Minaj -- X-Games Surprise ... My Man Meek Mill Is the Boss!! (VIDEO)

Nicki Minaj ain't afraid to share her shine -- even though she headlined at the X-Games ... she gave Meek Mill some stage time too, and the crowd erupted.

Nicki surprised the crowd in Austin by bringing Meek out during Friday night's concert. They performed his hit "Ima Boss" together.

Here's the thing -- neither one will say for sure they're engaged ... even though Meek iced up Nicki with a huge heart-shaped diamond a few months ago.

But c'mon ... would Nicki let "just a boyfriend' get on HER stage, and say HE's the boss?

Hell, nah ...