I sent Nick back to his agency after the memories mission. It's been a few days in-game and he never made it back there and he's not still at memory place.

I decided to use console command to port to him but when I do I just fall onto a tarp roof on a structure off the left side of the news stand in Diamond City and die. I've checked in, out, around, and above Piper's place and he's nowhere to be found.

Any have a similar situation or any ideas on how to resolve?

Wrong forum, try spoilers and hints.

Use the console to move him to you, not the other way around.

...delete pls

Try reload the game to any previous point before you sent him back. Then... Send him back again and check if its ok.

Didn't know about that. Will try to do that, I've lost Piper and choose Stronger to replace her.