Phone soft bricked, Nandroids not working, TWRP is still functional, no OS installed.

Tried to switch off of CM 12.1 back to stock. Wiped cache, dalvik, system, and data.

Annnnnnd now it's broken.

However, TWRP is still here. Any suggestions would be greatly appreciated. This is my primary phone. Thank you.

Also: command "adb devices" is not listing my phone when in fastboot mode.

THANKS AGAIN <3