There is already a file called `/home/alessiomtx/.config/tint2`, but it is not a directory.
Maybe you meant to edit `/home/alessiomtx/.config/tint2`?
If you really need a file called `/home/alessiomtx/.config/tint2/tint2rc`, move the existing file `/home/alessiomtx/.config/tint2` out of the way.
mv /home/alessiomtx/.config/tint2 /home/alessiomtx/.config/tint2.old
mkdir /home/alessiomtx/.config/tint2
But maybe that `tint2` file is some old name and the file should be moved to `tint2/tint2rc`?
mv /home/alessiomtx/.config/tint2 /home/alessiomtx/.config/tint2rc
mkdir /home/alessiomtx/.config/tint2
mv /home/alessiomtx/.config/tint2rc /home/alessiomtx/.config/tint2/