Talking about NC itself separately does not make more sense in I-485 processing, because an I-485 will not be adjudicated unless the Background Check has completed, not subject to just Name Check alone.
Normally Background Check takes longer time than NC.
So I assumed OP was referring to Background Check rather than NC, even though she did write so.
Thank you for your clarification.
For those who are not clear about Name Check and Background Check, please refer to this.