As others said, RPI will def be the nerdiest. That said, there are plenty of nerds and academics around (I probably see more as a CS major though). I think the distinction at Northeastern is that a lot of the nerds here are not the classic externally nerdy ones - once you get to know people, you really see it more.
I’m not personally one that goes as much on the geek side, but I know plenty of friends who go to stuff like Magic tournaments, are into anime and will go to con’s, cosplay, etc. It’s not a huge community, but it is there. Again, you’ll fund much more at RPI. I know a few CS/Engineering and Theatre people - my RA freshman year was actually civil engineering and theatre. He’s currently working in theatre and education, actually. The ones I know aren’t the external nerdy you mentioned, though.
For what it’s worth, I absolutely love the CS program here and would be happy to give more info there! If you want a good summary, check out this essay by the founder of the current curriculum here - he’s teaching the intro class in the Fall, actually!
http://www.ccs.neu.edu/home/matthias/Thoughts/Growing_a_Programmer.html