This
Nut usually has a petty tough time of things, ending up 'rounded' off, and cross threaded! Thankfully it is inexpensive enough to replace.
For other useful nuts and fasteners for use now, or in the future browse the schematic for your model, and make sure you have ALL of those important fasteners when you need them most!
Other nuts you may wish to purchase at the same time:
0914004001
0914004002
0914006025
0914008008
0914008021
0914010027
0914012039
0914016002
0914024007
Please make sure part numbers ordered are compatible with your model. Genuine factory specified parts are frequently great value and ALWAYS great quality. Use genuine factory fasteners - why take the chance with any other type!