In the YouTube Video below by Jackson Krueger Sports the narrator explains the play from beginning to the end.
It clearly shows Jonathan Abram celebrating prematurely instead of turning his head to find the defender who forced Nacua out of bounds.
That may have contributed to why Abram was released. It's the little things that oftentimes lead to the success or failure of a play, making a team or not.
He could have made the block on the man that made the play, but he didn't finish the play as he should have which cost the Saints a Touchdown. Big Mistake!
You can decide for yourself if he stepped out of bounds. From the camera angle in the video, it's hard to tell as the defender went through an oblivious Abram to force Nacua out of bounds. It appears as though his left foot planted on the edge of the white sideline stripe at about the 3-yard line.
Credit is due for the hustle play of the Titans defender, #89, TE Thomas Odukoya, who ironically, made the Titans initial 53-man roster yesterday. They kept 5 TEs.
Also, my OP was a comment made without reviewing the play. All Saints players except for Abram made nice clean blocks, mostly just sealing off the defenders. My apologies for including Rico Payton in the comment "Saints players running like cattle inside the 10-yard line that got caught up watching". Payton identified the immediate threat and what appeared to be the last defender and got in front of him to shield him from Nacua. The Fail belongs soley to Jonathan Abram.
Jonathan Abram doesn't block, cost team touchdown | New Orleans Saints Vs Tennessee Titans
I would have put Abram on the PS just for that. My thing is we don't know and neither does the guy that posted the vid if he stepped out of bounds because they never showed a reply of him stepping out. No one has