I'm a little confused as to how you came about the error message " Attempting to update axis data range with nil series min or max. Axis range not updated." Since you must provide a datasource to the chart, and the method -numberOfSeriesInChart: is a required method, you must have been returning something from it prior to returning 0?
It sounds to me as though your datasource was telling your chart that it had series, but no datapoints. The chart is then attempting to automatically update its range to span your datapoints, but it can't update to a range of 0 or nil, so it skips the update. This error message is probably a little superflous. All that is happening under the hood is that the range is being set to our default of -0.5 - 0.5 for both the X and the Y axis.
We've got a task in our backlog to improve our error logging so that users can disable / enable certain levels of logging, but I don't have any timescale as to when that will be available. I'll raise this scenario in our back log so that we're aware another user has encountered the problem, and we'll get back to you when we've had a chance to improve the chart's logging.
With regards to the best solutions: it doesn't really matter. Whether you provide 0 series, or 1 series with 0 datapoints, the chart isn't doing anything dangerous so it shouldn't affect your development (apart fromt the needless log! )
If you've got any further questions feel free to give us a shout either here, or via firstname.lastname@example.org.