Nexus Sprint Planing 81 people. How do you imagine it

The Nexus Guide says:

During Nexus Sprint Planning, appropriate representatives from each Scrum Team validate and make adjustments to the ordering of the work as created during Refinement events. All members of the Scrum Teams should participate to minimize communication issues.

Is chaos likely where Scrum Teams provide appropriate representatives, and the members of each team can communicate with whoever represents them?

In person? Or over digital conferencing?

Digital conferencing is my preferred method for oversized groups. I would suggest all members be logged into the digital conference and muted. Team representatives/product owners/scrum master/guests be in a meeting room.  Start meeting with a short ‘rules’ explanation and introduction of the in-room individuals.  Representatives generally have the content they need from the team already but if a question arises, the team member is ready to answer. Cisco's Webex has a 'raise hand' feature that makes it easy to see if someone online has a question or comment.

Someone needs to be elected controller and keep close watch on the digital attendees. I generally steal an attentive Project Coordinator or JR PM for that. It's not traditional but I find that the Team needs to be honed into the meeting content, not controlling it. PCs are my favorite for this since they are also used to taking meetings minutes and action items down.

Prior to breaks, I announce the exact minute all attendees need to be ready. After breaks I like to read off a 2-3 sentence re-cap. It becomes hard for everyone to stay focused after passing the first 4 hours.

I'm interested in hearing how this goes for you...

As far as I can see, the best solution is really video conference as Tesla said.

But still, from my perspective, it's better to have meeting only with representatives 3-9 people.