This has been a long standing limitation in OOo and now LO. You can use Named ranges as source for Pivot tables but not for charts. This would allow to have charts defined for later data input (currently that is not possible because the data range is automatically reduced to cells containing data) See this topic as an example (there are many others) http://ask.libreoffice.org/en/question/19627/calc-charts-automatically-increasing-data-range/
Added related Apache OO issue to See Also list. Version set to Inherited from OOo.
A workaround is to select an additional empty row (above and below) for the Data Range and ensure this option is selected: Tools > Options > LibreOffice Calc > General > Input Setting > Expand references when new columns/rows are inserted Inserting a new row beneath the last row will then automatically update the chart as expected. Same effect if inserting a new row prior to first row of data.
(In reply to comment #2) > Inserting a new row beneath the last row will then automatically update the > chart as expected. Same effect if inserting a new row prior to first row of > data. Thanks. I already do that. But I hope that someone actually adds this feature. It doesn't make sense that you can use Named ranges for some features but not for others. It's inconsistent and unintuitive ;)
This issue is connected to bug 64086. The missing ODF feature is handled in https://issues.oasis-open.org/browse/OFFICE-2081
*** Bug 132647 has been marked as a duplicate of this bug. ***
Still no fix after 7 years? I think named ranges are rather useless if they cannot be used in charts.