I can handle some nns as full names, but not all. I tend not to like names that end in "-y" or "-ie", like
Millie or
Bobby, because they sound too cute to stand alone. Even some names that don't end in "-y" or "-ie", like
Jim, sound too insubstantial to use as full names. I think I can best tolerate nns as full names when they don't sound very similar to their original name, like
Jack or
Molly.