You can re-install grub by booting into kali live USB. Here is the list of commands you need to enter-
Code:
sudo mount /dev/sda* /mnt
sudo mount --bind /dev /mnt/dev
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
sudo mount /dev/sda** /mnt/boot/efi
sudo chroot /mnt
grub-install /dev/sda
exit
sudo umount /mnt/dev
sudo umount /mnt/proc
sudo umount /mnt/sys
sudo umount /mnt/boot/efi
sudo umount /mnt
Replace * in sudo mount /dev/sda* /mnt with your linux partition assigned value.
Replace ** in sudo mount /dev/sda** /mnt/boot/efi with your EFI partition assigned value.
Use fdisk -l to list all partitions.