Every time I try to export my object as a .nif file, it gives me some error about not supporting non-uniform scaling and rotating on "cube.003", an object that doesn't even seem to exist or did exist but has been deleted.

Thanks in advance,

Bone_Collector

select all and hit ctrl+A
if this doesn't work be sure to only select the items you need to export, it will ignore the nonexistent item

NVM, already fixed it

ok then save the thing as a blend file and open a new blend file, go under file and hit append or link. Once you do that chose the objects that you had. then export that file and it should work