What can I do in my 3 hr 10 min layover at narita airport?

I will be going to Hong Kong on may 23 and will be laying over at narita for 3 hr and 10 min. I will arrive at 3:20pm and depart at 6:30. I realize from other posts that I can't go out and explore narita due to lack of time therefore what can I do specifically to burn the time? What restaurants should I check out?

You won't even really have 3hr and 10 min, you will spend time deplaning the arriving flight and boarding the departing flight, so about 1/2 hour each, now you're down to 2hr and 10min, next deduct time getting through the airport between gates, another 1/2 hour, now you're down to 1hr and 40 min… Yep find a restaurant and also grab anything you might need in flight from the shops, hit the duty free, etc.

Nothing much you can do. Just going through transit security can take up 30mins.
Just check out duty free

These days, there's good shopping in Narita Airport with "normal" prices. I think big Japanese retailers see their NRT shops as a branding exercise rather than a chance to to exploit captive customers. There's Mujirushi, Uniqlo, and so on. There are some decent bars with reasonably priced draft beer after security on the departures side. Visitors to Japan used to buy cameras and electronics. Nowadays, visitors to Japan gotta buy a hoodie and some stationary.

Find something to eat/drink, and look for a gift for yourself or friend/relative.

Eat and go shopping. Jump in a massage chair, and go to the Observation Deck.

Use the toilet. More comfortable than on the plane.
Get a little to eat and maybe shop.
Seriously you know to the MINUTE the time you have?
You really have just over an hour. From time you get off first flight to time you need to be on board your next one.
Your two flights might be close by to each other or a very long walk between them.

https://www.narita-airport.jp/en/shops

Read a book. Have a meal. Look at the shops. Go to the Observation Deck.

Basically, the same thing you do to burn time in any airport. You'll be spending about an hour in the bus, and you'll be able to look at all the pretty signs and stuff. After you arrive, you'll be going through check in, security and all that, so you'll probably have time to grab some Starbucks and get on your plane. There are some shops past security, but you really don't want to miss a flight because you've been browsing shops. If you are very fast, maybe you can spend 15 minutes up at the good shops on 4th and 3rd floor after check-in and before you go through security. I wouldn't spend too much more with your connection.

By the time I got there everything was closed except for 1 gift shop so I got water and some gifts for my friends, walked around a lot, looked out the windows and sat down to kill time.

It is not enough time to exit the airport and go anywhere except 'outside" to get some fresh air.