Narita Airport to Nagoya Airport

This will be the first time alone that I will flown in Japan. I will be flying on Japan Airlines and I will be arriving in Terminal 2 from Los Angeles. Now I will have 1 hour and 45 minutes until my next flight departing for Nagoya (also with Japan Airlines). I was wondering about a few things.

Will I need to get my luggage at Narita airport and/or check it in again with Japan Airlines? All my flights are on one ticket(from Las Vegas to LA to Narita to Nagoya) by the way.

Not sure, but possibly....I seem to remember all passengers going through customs and immigration at Narita (like in LA on your way back to Vegas).
I hour 45 mins is HEAPS of time between flights: Narita customs and immigration is amazingly efficient and quick: both times we have been either waiting for the bus or waiting for the train after activating JR Passes within 45 minutes. Staff at Narita are very helpful, and airline cabin crew will be able to tell you what to do as well. Narita is very well signed in English

I believe that the flight from Narita to Nagoya is considered an international flight, which means that you don't have to pass immigration until Nagoya, and your luggage will probably be sent directly to Nagoya. The check-in personal at Las Vegas Airport will be able to give the definite answer regarding your luggage.