Narrative:

We were cleared for the RNAV rnp Z 20R from joglo. Approach control had been advising another company aircraft landscape north on 20L of a small aircraft that had penetrated the class C and advised them that the aircraft's location was on final to 20L tracking west. We knew that aircraft would be an issue for us and I (pm; pilot monitoring) began to scan for the traffic. Approach then advised us that after 90 degrees the aircraft would be on/near our course. I spotted the aircraft and advised the PF (pilot flying) to arrest the rate of descent and they used V/south. As they did we got a TA and then immediately following an RA to not descend. The PF never got sight of the traffic but I felt the corrections were proper. In my estimation the traffic flew 200 feet below us on the approach course; and with approach control's help and the RA; this would have been a near miss. On landing we received an FAA phone number and after we had parked the aircraft I called and reported my recollection to them.I am unable to provide insight because this was an aircraft that wasn't talking to ATC. The traffic was a threat and we all worked together to maintain safety of flight.

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Original NASA ASRS Text

Title: Air carrier Captain reported an NMAC on approach with aircraft that penetrated BNA airport airspace.

Narrative: We were cleared for the RNAV RNP Z 20R from JOGLO. Approach Control had been advising another Company aircraft landscape north on 20L of a small aircraft that had penetrated the Class C and advised them that the aircraft's location was on final to 20L tracking west. We knew that aircraft would be an issue for us and I (PM; Pilot Monitoring) began to scan for the traffic. Approach then advised us that after 90 degrees the aircraft would be on/near our course. I spotted the aircraft and advised the PF (Pilot Flying) to arrest the rate of descent and they used V/S. As they did we got a TA and then immediately following an RA to not descend. The PF never got sight of the traffic but I felt the corrections were proper. In my estimation the traffic flew 200 feet below us on the approach course; and with Approach Control's help and the RA; this would have been a near miss. On landing we received an FAA phone number and after we had parked the aircraft I called and reported my recollection to them.I am unable to provide insight because this was an aircraft that wasn't talking to ATC. The traffic was a threat and we all worked together to maintain safety of flight.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.