The problem here is that the charting subsystem requires that stacked elements be in different series in the table. Your search has to yield something like:
User 1 2
----- --- ---
User3 2.8 1.5
You can convert your table to one like this by renaming values(Hour) to vals and adding at the end:
| mvexpand vals | eval counter=1 | streamstats sum(counter) as instance by clientip | chart first(vals) as val by USER instance
Here we break each user into their individual values, use streamstats to accumulate an instance count, and reformulate the chart using the USER and instance.
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