I would suggest you will be lucky if you manage to achieve this if these are separate tickets, which seems to be the case. What happens if Garuda refuse to check through? Will you have enough time to exit, claim baggages and make it back to check in a different terminal and make it to the plane. 2 hours seems to be far too tight. Do you have a backup plan if the Garuda flight into NRT is just late so you can't make your next flight?