He likes you. A lot. This nervousness is a sign that he is attracted. He may be waiting for you to talk first. Break thru this nervousness on both your parts and talk. Once you do, you may find it easier than you think.
Yes it's that simple. He likes you a lot.
He's trying to normalize himself when he's around you, so he overcompensates at times (completely ignoring you).
(If he was here asking this question I'd tell him the same thing) You talk to him by going up to him and telling him - very chill, but very honest - that you like him but you're shy and don't know what to talk about when you're around him...and that you're not sure if he feels the same way.
When he manages an affirmative out of his nervous mouth, both of you then talk about how awkward you two are when around each other. The best way to break the ice is to ram it head on lol