In some convenient cell enter =MID(LEFT(CELL("filename",A1),
FIND(".",CELL("filename",A1))-1),FIND("[",CELL("filename",A1))+1, 255)
This gets the file name into a cell
Make the chart and add a tile (anything will do)
Click on the tile in the chart, in the formula bar type = and then point to
the cell with the formula given above.
best wishes