We can wrap the labels in the label cells, and then the labels in the chart axis will wrap automatically. And you can do as follows:

1. Double click a label cell, and put the cursor at the place where you will break the label.

2. Add a hard return or carriages with pressing the Alt + Enter keys simultaneously. 

3. Add hard returns to other label cells which you want the labels wrapped in the chart axis. Then you will see labels are wrapped automatically in the chart axis.

Note: If the chart area is still too narrow to show all wrapped labels, the labels will keep rotated and slanted. In this condition, you have to widen the chart area if you need the labels wrapping in the axis.

Tip: Batch remove all line breaks/numbers/letters/special characters from selected cells
Kutools for Excel’s Remove Characters utility is designed to remove all letters, all numbers, or special characters (such as bullets) from text strings easily. It’s also able to remove all non-numeric characters, non-alpha characters, or non-alphanumeric characters from specified text strings easily.

Some users may want to wrap the labels in the chart axis only, but not wrap the label cells in the source data. Actually, we can replace original labels cells with formulas in Excel.

For example, you want to wrap the label of "OrangeBBBB" in the axis, just find out the label cell in the source data, and then replace the original label with the formula ="Orange"&CHAR(10)&"BBBB".

And you can wrap other labels with the same way. In our example, we replace all labels with corresponding formulas in the source data, and you can see all labels in the chart axis are wrapped in the below screen shot:

Notes:
(1) If the chart area is still too narrow to show all wrapped labels, the labels will keep rotated and slanted. In this condition, you have to widen the chart area if you need the labels wrapping in the axis.
(2) The formula ="Orange"&CHAR(10)&"BBBB" will wrap the labels in the source data too in Excel 2010.

Save chart as AutoText and reuse it with only one click in Excel

Kutools for Excel’s Auto Text utility can save a selected chart as an Auto Text, and you can reuse this chart at any time in any workbook by only one click.