car seems to slightly fish tail when ever I hit a bump/ pothole

Worn struts and/or suspension.

I have the same problem on a 2014 Murano with 60k. The problem started last month. I began by taking it to an alignment shop. They told me the back shocks were shot. They align it and replace the shocks. It didn’t help. They gave up. I took it to another mechanic who replaced the rear tow bars. That didn’t help either. Now I have 900 into it and no solution. Neither mechanic can figure it out.