It's a mathematical equilibrium that, if used correctly, allows you to play a shove/fold game that guarantees you not to lose money. It is Sklansky but then instead of showing your actual hand you can tell your opponent your range and he still cannot construct a strategy that would win money against you.

Nash works great for heads up scenarios when you are really short stacked and are effectively only shoving or folding. That means when you have 8BB and shove all hands in the nash chart, you must shove all of them (including AA) to make it work. As soon as you have a stack where you can actually raise/fold it will conflict with nash and it is generally more profitable to actually deviate from it.

Note that it is an equilibrium which means you cannot lose money but if your opponents play well you also don't win very much. I typically use it when I have no reads on my opponents or have no general clue how wide they will shove/call so at least I won't make a mistake. As soon as I get more info (calls too much, shoves less) I will make the adjustment and call/shove tighter/lighter.

Typically people like to shove a bit tighter than nash so when you are in SB here I shove K2s like nash allows me to but if I'm BB I fold to this shove despite nash tells me I am not really making a mistake. It is because most people don't shove nearly wide enough in those spots and by calling slightly tighter I will make more money. It also works for shoving, if my opponent is calling way too loose I am not shoving 78s because it is just wasted on him.

Also look up Sklansky because it shows you what hands you can shove and turn your hand face up and there is nothing your opponent can do about it. When you are in SB and fold a hand that is in that chart, you truly are making a huge mistake. The nash chart has basically all the hands in Sklansky but it is a bit wider. Deviating from nash sometimes is perfectly fine as long as you have good reasons to.

That doesn't change how many orbits he will survive by folding.

At this point, he shouldn't be trying to survive.

At 10bb deep, you could shove something like 56% of hands, and tell villain this is your exact range: 22+ A2s+ K2s+ Q2s+ J3s+ T5s+ 95s+ 85s+ 74s+ 64s+ 53s+ A2+ K2+ Q7+ J8+ T8+ 97+ 87

...and there's nothing he can do to stop your shoving range from being profitable.

K2s is a very clear jam. It's unexploitable up to about 19bb if you solely use Nash push-fold ranges (i.e. you don't ever limp or minraise, and you play AA exactly the same way as 76s).

I don't disagree. But it's still irrelevant to what I said in the context in which it was said.

I agree with you, and this is why I shove K2s, I have to do something to make deeper run, perhaps a FT, if my goal was do survive to next payout jump I would fold this hand, but as I said I have to do something and this was a good situation...

One question: What if button raise like 2x, will be that ok to shove?

Depends on reads and table dynamics, of course, but as long as the button doesn't have either a very large of very small stack, yes.

I say yes because you would still be in the same position chipwise as the original scenario if you folded.

Now, if you were big blind and the button raised and the small blind shoved, that might be a different story.