Playing 1/2 and get in to the same spot against same opponent twice.

Hero MAWG playing well. TAG image but not sure if matters against opponent.
Villain is 70ish. Initially thought he was typical OMC. Saw him check call flop and turn on two previous hands and lead both rivers with boats.

Adjusted my read on him as session played out. More of an OMSpazz. Started attacking all pots that were checked to him. Caught him bluffing two times later for big pots.

First hand is multiway limped pot. Im in pos and have villain covered. Flop a set of 2s and make a pot sized bet. Villain calls. Quads on the turn goes check check. He leads river and I minraise, maybe slightly larger. He folds.

Second hand. I open 66 from CO and villain calls in BB. Flop is Q65. Check, I bet half pot and he calls. Turn is a queen. Check, check. He leads river, I raise and he folds.

I guess I don't want him to get away on turn but looking at it now it seems I should just be sizing down for value and getting all 3 streets. I know when to check one pair hands aiming to get 2 streets.

So, not really a question about these particular hands but any guidance on what my thought process should be when making big hands against opponents that I perceive to be nitty and passive?

In regards to your general question, they either have something to call with, or they don't. If you check, that is unlikely to change OTR, so bet now and hope for the best. If they fold now, oh well, they weren't likely to give you any more action OTR.

IRT the specific V you mention, float the hell out of him and raise river with ATC until he starts calling.