it's a bishop for knight in my favor
So what? You will have moved the knight 3 times to your opponent's bishop 1 move and you will have improved your opponent's position by opening the f file for him. So, not in your favour after all.
the bishop makes my position slightly vulnerable because of the pin on the queen
No, it doesn't. If it ever becomes a threat you can nullify it with NxB. Until it becomes a threat you are reacting to a phantom.
the knight outpost is appealing but it can be kicked with c5
To which you can react with NxB! Again, you are reacting to a phantom. Although Ndb5 would be much better increasing the pressure on the backward and now weak pawn on d6.
The reason you won the game is that your opponent blundered. His reply to your Rad1 of moving the knight back to f6 for no good reason was terrible. Far better would have been to kick your bishop with e5. With the knight on g4 protecting e5 this is possible and very good. With the knight back on f6 this is not possible.
As is often the case the move you chose, NxB, releases tension unnecessarily, and in this case in your opponent's favour. Playing Rad1 retains the possibility of NxB if it looks better later and it reinforces the center and places a rook opposite black's queen. It is just a much better move.