I've been playing a bit of NLO8 these past few weeks, and I've noticed quite a few people just shoving incessantly pre flop, even with 50/60/70bb's - what's the deal? What's the strategy behind this? How do we combat it? Should we? What % of hands can we look to call off if we have say 50bb's vs a 60bb shove?

I'm starting to get my act together with the game a bit now in terms of solid starting hand selection and position, but struggling to find anything where I can improve my strategic knowledge of the game. At the lower limits, it appears that if you just play solid hands, look to flop well and look to go for value across three streets, you get called off by a real wide range of junk - is it really this simple or have I just found myself up against some really bad players?

Against huge shoves you don't need to call wide. AA, good AK2, A2ds with decent kicker.

Yes, many players are very bad in poker.

How about hands like:

Ax 9y 3y 2x
A- Kx 3x 2-
A- 4- 3x 2x
Ax Ty 4x 2y

I think my main worry is, am I missing spots by folding certain hands and making mistakes calling certain hands in these spots pre flop.

Don't know, which stake you are playing at (I'm a microfish).
In terms of preflop shoves, it's more or less a mathproblem, where Amok already told you, which hands to call with.

Also factor in the rake.
For example at 0.01/0.02 NLO8 zoom on stars, you need 52% equity to call a 100 BB shove profitably.

Hands like A239 don't do too well, a 9 high flushdraw is often dominated and the 9 often doesn't play. Also all the low rundowns don't do too well (like your A234).

However, if it goes 3+way all in, then hand features that give multiway equity are the ones to look for. Those are usually high flushdraws and good lowdraws. In that situation the small rundowns perform much better.

A- Kx 3x 2-
it's a great hand, one that I'd always call against a wide shove

Ax Ty 4x 2y
Ax 9y 3y 2x
decent hands certainly, especially 3-way

It's really great when you can determine whether or not someone always shoves AAxx preflop. It's nice to be able to play KKxx as top set on a board of AK3 just on the fact that they saw the flop.

How would you play KK as a middle set?

When players are shoving 60+ BB they will mainly have AA and just don't know how to play it. I wouldn't call these unless you have AA with low AKK2/3/4 etc. A256 double suited and hands like this are behind, and if villain is a massive fish, then occasionally ahead, but not worth it.