Nexus: Team members of one team supporting the other team?
Two teams working on the same product. While one team has problems finishing their sprint because of a rather complex story, the other team is doing well and one team member asks to pull another simple story from the product backlog into the current sprint, being confident to finish it until end of sprint. Some other member suggests that the team member should help the other team getting their complex story done. The complexity of the mentioned stories does not necessarily reflect the business value provided by the stories.
How could this situation be handled, if both teams agree that it would actually be possible according to estimation? The team might insist on protecting the integrity of their team and velocity. The product owner might insist on having the final say on what to do next from the backlog to have most value generated for the product increment.
I'm rather uncomfortable with "one team has problems finishing their sprint because of a rather complex story, the other team is doing well".
In Nexus, the input is not a bunch of separated increments but an "integrated increment".
If the complex item is compulsory to meet the Nexus goal, then it is a top-priority for the full Nexus, not only for one single team.