ITerm2 Closes Immediately After Opening
Move the following directories and files somewhere else to back them up.
~/Library/Application Support/iTerm2
~/Library/Preferences/com.googlecode.iterm2.plist
~/Library/Preferences/com.googlecode.iterm2.private.plist

See if iTerm2 starts up without crashing.  You may need to redo all your settings or attempt to decipher them from the backed up files. You can open the PLIST files in Xcode in an easy to reference view.