Elliott was briefly detained but not arrested in the incident, when a security guard fell to the ground after being bumped by the running back.
The NFL said it conducted a comprehensive investigation that included interviews with multiple witnesses, including security personnel and others with direct involvement, as well as a review of documentary and other information.
Elliott, 23, met with NFL commissioner Roger Goodell for several hours on Tuesday to discuss the incident and what he had learned.
Elliott issued a statement following the meeting in which he said he had made a poor decision and needs to work harder to not put himself in such situations.
"I've worked hard to make better decisions and to live up to the high standards that are expected of me," Elliott said in the statement. "I failed to do that here and I made a poor decision.
"I need to work harder to ensure I do not put myself in compromised situations in the future. I am rededicating myself to use all of the resources that the league has made available. But in the end, it is up to me and I am determined not to be in this position again."
Elliott could have been fined or suspended under the league's personal conduct policy, which does not require an arrest or conviction for a player to be penalized.
But Goodell determined there was no violation and no further action was warranted.
Elliott, a two-time Pro Bowler, was suspended for six games by the commissioner in 2017 for violating the personal conduct policy. He had been accused of domestic violence by his former girlfriend in Columbus, Ohio, in 2016. Elliott was not arrested or charged by the police, but the league believed it had enough evidence for the punishment despite the lead investigator recommending no penalty. Elliott fought the case through the legal system before eventually relenting and serving the suspension.
Cowboys owner and general manager Jerry Jones said during the offseason he did not believe Elliott would face any sanctions from the NFL over the incident in Las Vegas, and executive vice president Stephen Jones said the incident would not affect the negotiations with Elliott's agent on a long-term contract.
ESPN's Todd Archer contributed to this report.