Hi @shivmahar83 Do like this and see whats happens.
In the N5 factory folder there is this image-hammerhead-m4b30z.zip, extract it, in there you have another set of images.
right click an empty space in the folder, click 'Open terminal here', run these commands in terminal:
sudo fastboot oem unlock
sudo fastboot flash boot boot.img
sudo fastboot reboot-bootloader
sudo fastboot flash system system.img
sudo fastboot reboot-bootloader
sudo fastboot flash cache cache.img
sudo fastboot flasch recovery recovery.img
sudo fastboot reboot-bootloader
In bootloader run the Ubports installer