You can calculate Nash equilibrium only when you know the strategies of your opponents. There is no single winning strategy in complete No limit Holdem, so you

You can calculate Nash equilibrium only when you know the strategies of your opponents. There is no single winning strategy in complete No limit Holdem, so you don't know how your opponent is going to play. It's theoretically possible to find Nash equilibrium over all possible strategies but that's not winning strategy. You just lose as little as possible. You lose against most/all strategies. Take for example Kuhn poker (https://en.wikipedia.org/wiki/Kuhn_poker https://en.wikipedia.org/wiki/Kuhn_poker). It's very simple but first player has several optimal strategies.