If you have checked bags, don't forget about the 1 hour cutoff at HND, which really means you only have 2.5 hours to make it from arrival at NRT to HND. This will be extremely tight with no room for error. Keep in mind this is the bare minimum MCT (3:30).

If you misconnect you'll be rebooked. But if your inbound is substantially late I'd probably try getting it sorted before leaving NRT, as it'd be evident that you won't make the connection anyway.