Chicago 17 - Organisation as Author - Abbreviations
To get straight to the point, I will quote the Chicago Manual of Style official guide (17th edition):
15.37 Organization as author in author-date references.
If a publication issued by an organization, association, or corporation carries no personal author's name on the title page, the organization may be listed as author in the reference list, even if it is also given as publisher. To facilitate shorter parenthetical text citations, the organization may be listed under an abbreviation, in which case the entry must be alphabetized under that abbreviation (rather than the spelled-out name) in the reference list.
ISO (International Organization for Standardization). 1997. Information and Documentation-Rules for the Abbreviation of Title Words and Titles of Publications. ISO 4:1997. Paris: ISO.
NISO (National Information Standards Organization). 2010. Bibliographic References. ANSI/NISO Z39.29-2005. Bethesda, MD: NISO, approved June 9, 2005; reaffirmed May 13, 2010.
(NISO 2010) (ISO 1997)
Why does Citavi not support this? There is already an abbreviation field for organisations, which works nicely with APA but not with Chicago. In the in-text citations, organisations always appear in their full name.