On my list I have [name_m]Theodore[/name_m] nn [name_m]Todd[/name_m]. I just skipped the E you would normally use for [name_m]Ted[/name_m] and went straight for the O.
Also, if you don’t mind a bit of a stretch, I could see [name_m]Thomas[/name_m] nn [name_m]Todd[/name_m]. If it works for [name_m]Abraham[/name_m] Lincoln’s so [name_m]Thomas[/name_m] nn [name_m]Tad[/name_m], I could see the same idea working with nn [name_m]Todd[/name_m].