No, it's not nostalgic if you have to research what you should react to before hand. What's nostalgic is what you remember of the franchise.
I disagree. Nostalgia is a desire to return to something in one's past. It doesn't matter if you augment your memory with research, it's still nostalgia if you're going back to days gone by. Grabbing out a yearbook so you can remember the name of that guy you were in drama club with doesn't mean you can't have bittersweet memories about your times together. In fact, I've found that, when sharing old stories with my family, hearing something I didn't recall on my own only serves to heighten nostalgic feelings.
In fact, much of what the Nostalgia Critic does is anti-nostalgia. He has no desire to return to many of these movies, and actively disillusions as many fond memories as he can. It's a nice bit of comedic irony, really. The normal source of melancholy in nostalgia is wishing to return, but knowing it's not really possible. With the critic, the movies are out there to watch, but you don't really want to return to them.
Oh please.
His reviews are about what he remembers and his impressions as he watches the thing. He then scripts those thoughts. It isn't really about research.
Like, there are many times I'm watching something and I can't remember a name of a character...it doesn't stop me from riffing on it.
It doesn't bother me that he gets things wrong, it bothers me that he prefaces his segment by telling people he doesn't remember. I think it detracts from the humor to say something like that.
It's one thing to say "I can't remember who this character is, but..." and another to skip that, call the character by some mocking nickname and get on with the joke. The audience doesn't need to know you're calling the bad guy "Suzy" because you didn't remember his real name. Just throw a name out there and get on with the gag. Be spontaneous and off-the-cuff, or do the research and be a little more thoughtful in your humor, but don't apologize for it whatever you do.