Clean flash without SDCard So, I want to flash a new rom with gapps.
I've done this before, but I always did a factory reset and flashed the new rom which was in the downloads folder in my phone.
I was wondering, if I wipe my data and system via twrp, will my internal partition be wiped? Because if it does, I have nothing to flash cause that's where my rom is stored.
I have the Samsung Galaxy Nexus which doesn't have a sdcard, so that's not an option.

Thanks in advance.
You don't have to worry if your internal storage gets wiped.

There is another way called "ADB Sideload" which allows you to push and install a zip from your computer using CMD (Windows) or Terminal (Linux)

Steps to use ADB Sideload


  
  Have a recovery installed on your device that supports ADB sideload like TWRP 2.3 or higher. The stock recovery on JellyBean and later maybe have it.
  Have newer ADB binaries installed on your computer
  Set the device into ADB sideload mode. In TWRP you do this by going to Advanced then ADB Sideload.
  From the command prompt (CMD), type adb sideload /path/to/rom.zip
  


Reference