B737 MAX 8 First Officer reported hearing a Maintenance person yelling about the aircraft about to lift off the nose due to a tail jack not being installed on the rear of the aircraft; during unloading of cargo and passengers.

Narrative

As I walked down the stairs to conduct my walk around on a MAX; I heard a man (Maintenance guy) screaming to have the provision trucks back up from the aircraft. I then asked him what was going on; and he pointed to the nose strut of the aircraft which appeared to be at full extension. He said the aircraft was on the verge of tipping back onto its tail. I don't have any factual information as to why; but it appeared the Ground Personnel had offloaded the forward cargo area first and the Passengers were still deplaning from the recently arrived flight.My suspicion is that if the forward cargo area was empty; and the aft cargo bay full; and passengers deplaning (obviously from front to back); that the CG was continually moving aft at an unsafe rate causing the dangerous situation. I remained outside the aircraft and we gradually saw the strut extension reduce back to a safe position as more passengers deplaned the aircraft. The Maintenance guy said we were seconds away from having the aircraft tip completely onto its tail. There was no tail stand installed on the MAX.