Did I fry my ECU?

In theory it should not have hurt the ECU. The MAP sensor uses three connections. Power ground and signal. In function it works like a potentiometer. With it unplugged the ECU falls back to baseline programming and uses other sensor inputs. When you suddenly plugged it back in the system now had an input that it had to use. That may have scrambled it a bit.
Try disconnecting the battery for a few minutes to let the system forget the input and see if it clears up.

What is the issue you are trying to correct that prompted you to pull the MAP? It is possible that it is the root cause for the misfires.

MAP normally would not effect either of those. However, the knock sensor and a single cylinder misfire together would cause some stumbling as the engine uses the KS to adjust the timing and the misfire would throw the ECU off on its own.
Try the reset and we will go from there. Do you know the last time it had plugs or any other work done?

The hope was that the system would flush out bad data. The thing is that if you still have the misfire the engine will run bad, shaking and rough.

Is the part in the first picture what you unplugged, it is at the bottom of the other picture or was it the unit out in the intake tract? Just realized we may not be talking the same part.

Okay, that is a bit different. The MAF on Nissan vehicles does not like to be plugged in with the power on. The MAP that you referenced earlier would be okay, but the MAF is a different animal. With that it is possible that it damaged the ECU.