A big factor is what cabin you will be in. Traveling in business or first and no checked luggage, I have made it in 20 minutes. That involves being rather - err - brusque - in jetting past other pax on the way to the Immigration lines. My long legs help. From economy, you will be behind many more people but can still make up a lot of ground by moving fast and getting into the shortest line.

Either way, I agree with Mike. Just don't dawdle and you will make it easily.

Add: Christmas Day in Japan is no big deal, just another day. The major holiday there is New Years Day.