Air carrier pilot reported a near miss with another aircraft while on initial approach during night visual conditions. Flight crew followed the aircraft TCAS guidance to avoid a collision; and then continued the approach.

Narrative

This incident occurred while on a flight from ZZZ to CLT. We had arrived on the STCRW arrival and were advised that we would be getting the visual to 36C. After reloading the box with the new approach; I; as the PM briefed up the approach for the PF and we pressed on for the approach. In our descent into the terminal area approach gave us a 330 heading to intercept the localizer and cleared for the visual. We were also told of traffic that was on the left base for the 36L below us. I; as the PM; replied with Negative contact; searching". We actively searched for the traffic as we intercepted the localizer and started to descend down on the GS in approach mode. After selecting the missed approach altitude for the PF I had noticed a TCAS target on our PFD (Primary Flight Display) on the left side of the depicted aircraft. It had a diamond symbol as well as -5 in white. I immediately looked outside and saw the target approaching us at our 9 o'clock and low. At the same time we got an RA to level off. I told the PF to immediately level off as the TCAS continued to announce "level off". I had the fly to box in the HUD (Head-Up Display) as well. The TCAS blip continued to fly towards our aircraft and I recall seeing a -3 at one point next to the symbol. Approach then told us to contact tower. I said we were responding to an RA and if he had the traffic. He said that he did and that is why he called it out. I responded with "and that's when I said Negative contact". He then told me that they were busy working multiple sectors. I then switched over to tower and we continued the approach as the TCAS RA disappeared and the traffic appeared to be clear of us on the left. The rest of the approach was uneventful. I wasn't flying in the other aircraft that flew towards us but I can only speculate that they had either loaded the wrong approach in their box or were relying too much on visual clues and lined up for the wrong runway. I normally keep these reports as neutral as possible and only sticking to the timeline of events. I can not emphasize how close this was to being a midair collision over the town of Charlotte. The other aircraft clearly overshot their final either because they were set up for the wrong runway in their box or they just overshot the final for 36L visually and lined up visually with the wrong runway. When I flew military aircraft in formation this would've been cause for a breakout with a formation rejoin as the 2nd aircraft rejoining on lead had over shot the turn and was unable to join up in the proper position; and from what I could tell it seemed as though we had leveled off directly above them as they corrected their turn towards the wrong final. Had it not been for the RA call from our aircraft; I am not sure we would've been able to maintain visual separation with the other aircraft because I only saw him briefly before returning to my own instruments with the RA call. As far as recommendations go I have three clear ones that I walked away with that night. First off; there should be no visuals assigned at night. Second; making traffic calls from ATC should be advisory only and not an attempt to get the pilots to maintain visual separation if the traffic is called in sight. Finally; budget cuts causing single ATC operators to work multiple sectors is only going to lead to more disasters like in DCA."