This Natural profile parameter specifies the name of the environment-independent Natural nucleus if it is to be loaded dynamically and not linked to the environment-dependent Natural nucleus.

Possible settings	1 - 8 characters	Valid load module name.
Default setting	none
Dynamic specification	yes	Note: By specifying this parameter dynamically, you are able to use different environment-independent Natural nuclei (for example, for production and for testing) together with the same environment-dependent Natural nucleus without having to relink the nucleus.
Specification within session	no

Notes:

1. The profile parameter NUCNAME is ignored if it is specified in a parameter string activated by a SYS or PROFILE profile parameter or in an alternative Natural parameter module (as specified with the PARM profile parameter).

For further information, see Environment-Independent Nucleus in the Installation for z/OS documentation.