How to beat Nimzovich-Larsen attack ?

Before today I learned nothing about this opening. If white plays 1.b3, I would play 1. ..d5 or c5. Then perhaps my position soon became uncomfortable.

Today I checked the database, I found the main line is 1. ..e5. After 2. Bb2 Nc6, the bishop at b2 seems blocked by the pawn at e5 and black's kingside is safe. Now black is ready to play d5 to control the center.

However， this position is too strange to me. It seems there are still something complicated. In this opening, what should I be aware of as black?

There is nothing weird about it.  Here is the main line:

Thank you.

But, if black play 11. ..Qd7, attack the knight and try to go to h3,  it seems white is in a great danger.

1. b3 is a regular Larsen Attack.

The Nimzo-Larsen attack (which is much better) starts 1. Nf3 d5 2. b3 (instead of the Reti Opening, which plays 2. c4).  White develops the knight first to prevent 1. ..e5, leaves the long diagonal open for the fianchettoed queenside bishop.

a different way of tackling the b3 systems is to answer with a counter-fianchetto as early as possible. 1 b3 g6, and 1 nf3 d5 2 b3 g6, not minding that white can take on f6 in both cases, as at best it gives an equal position where both sides can play for a win but white has to prove it more in my opinion as black has the bishops.

Not at all.  Just a simple Knight move and Qe2 or Qf3 followed by a potential Qf1 at some point takes all pressure off of White and he is 2 pawns up.  If you research the line I gave, I did not go all the way to the end as there are options, like after 12...Bh3, there is Rf2 and Rf3, but all lines lead to either an advantage for Black OR a balance in material as White is going to have to return the exchange.  It usually ends up 2N+2P for R+B, unless White actually tries to hold the material, but then he is usually lost.  Black needs to get his pieces toward the White King quickly.  11...Qe4 with Bh3 and Ng4 coming in most lines is 3 pieces.  11...Qd7 and 12...Qh3 is easily countered by the White Queen.

I like to play against it b6! So 1.b3 b6 and see the expression on their face. Then I aim play Nf6, e6, d5, c5 , Be7/d6, Nc6/d7 let white give me hanging pawns then a pretty standard attacking formation pointed at whites kingside [so Rooks to e8,d8 Queen to e7 or Qdt-f5, Bishop to d6 , lift a rook, Ne4, push d4 ... . Since nothing here is forced, white has a lot of chances to deviate and black responds to the position on the board.

I just check the engine. Engine says black has an advantage about +2, so after Qd7 white is losing. But in database no one play Qd7, human player played as your line. It seems your line is a little old, last game was in 2007. Thank you anyway, I am grateful to have a discuss.

Playing e5 is what White wants. They want a central pawn target.

If you want to avoid a theory battle, an easier way to play against 1.b3 is to develop quickly and cleanly:

Then, as Black, all you need to do is develop your queenside pieces and remaining pawns (the queen bishop will likely to go b7, or possibly a6 ; the c pawn will likely go to c5; and the queen knight can go to c6 or d7, depending on which is best, and the d pawn will go to d6, or possibly d5).

one attempt which can catch white by surprise is to play for an early g6. 1.b3 1e5 2.bb2 nc6 3.e3 g6!?  and its not always clear how white should proceed.  Early f4 lines are not that poisonous here, and white doesnt have the glorious b5 pin (and is met by nge7), furthermore, the safe e3, nf3 c4 be2 nc3, d4 formation ends up being a line a tempo down in 1.b4!

maybe, they are some minor improvements from white, but this is not exactly a dream position. White's expansion is far slower than blacks. If white gets tempting to play d5, the outpost on e5 is far more annoying than if white gets one on d4 i have so experienced. Suffice to say if white doesnt want to fall into this passive position, he better know what he is doing. 

2 issues with your logic:

1) Which engine are you using?  If you even dare say the Stockfish Engine on chess.com, you have officially invalidated your argument.  It is Stockfish 10 with 1 CPU Core, it's a complete relic!  I use Stockfish 12 and also a more recent DEV build of Stockfish with 20 CPU core.  That is like putting Michael Jordan up against Homer Simpson's father in a game of 1-on-1 basketball!

2) Computers are HORRIBLE in the opening unless you specifically install the opening book (which chess.com does not do with their engine).  I have seen computers evaluate the Kings Indian as +1.6 almost the whole way through the game with White not being able to do anything.  A prime example is the following game where I had Black:

Never was it below +1, and yet, with computer assistance, White could not win this game.

Computer evaluations are not all it is cracked up to be.  Computers are best at middlegame tactics, not openings, endgames (unless it can calculate all the way to the end), or positional evaluations!

There is a pretty solid nimzo-larsen course on chessable, it shows you how to play it as white but I also use that as my anti-nimzo-larsen theory

I am agree with the idea that computer evaluations is not all.

But ...it is too much, I just use my computer analysis the position with Stockfish 12, after Qd7 the point is about 3. Black's Queen want to go to h3,then 0-0,Bg4.White can't 0-0 or 0-0-0. Here is a line, after Bxf6 white is still losing. Whether there is a way for white to save the game?