I have a Pioneer DJM 900NSX2 I need to output two track stereo for the audio AND I use a mic but want to be able to route the mic so it does NOT RECORD, follow?
Audacity will record whatever audio comes through the recording device selected in the Device Toolbar. There is no provision for signal routing within Audacity.
You may do better using software that is recommended by Pioneer, such as Traktor, Serato,… See the manufacturer’s documentation for details.