Rescue Kali

# Mount root partition:
sudo mount /dev/sdXY /mnt # /dev/sdXY is your root partition, e.g. /dev/sda1

# If you have a separate boot partition you'll need to mount it also:
sudo mount /dev/sdYY /mnt/boot

# Mount your virtual filesystems:
for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done

# Chroot
sudo chroot /mnt

update-grub