two key stakeholders - room for one item into sprint
What is the best approach when two key stakeholders ask for 2 separate items and the team has room for just one item into the next sprint?
What can be really helpful in this situation is to have a definition of value.
For example, it could be that your definition of value includes satisfying the organisation's strategy as best as possible. Or it could be regulatory, cost savings, etc.
The more clarity you have on your organisation's defintion of value, the easier it is to make a priority call like the one you describe. It will also tend to take some of the heat out of the situation, with the stakeholder who does not get their work done understanding the reason why this is happening.