Can you open a bag of chips and eat it in the store as long as you pay for it still?

Some will let you, some won't.

Yes of course you can.

I think if you have the money to pay, you can. Maybe they'd come to you and say if you are able to pay. I'm not sure about the law of it though, I'm just guessing

It’s somewhat tacky but usually tolerated.

Yeah..i eat my nuts in the store..then pay!

I can