Is the Nizmo-Larsen (1.b3) worth to be played?

1 b3 is just an opening you *play*. Studying variations just to realize that it is completely equal kind defeats the point. But if you want to look at something... 1 b3 d5 2 Bb2 c5 3 e3 Nc6 4 Bb5 is the sort of thing White is after, and you need to have some idea how to continue after 1 b3 e5 2 Bb2 Nc6 3 e3 d5 5 Bb5 Bd6. Anything else, you can make it up as you go along.

Be also aware that the Nimzo-Larsen can be played with 1.Nf3 first (Nimzovitch's way) to avoid the 1...e5 lines in the opening.

Some openings equalize more easily than others. In the Berlin, Nimzo-Indian, Queen's Gambit, etc, Black still has to work for equality, even if theoretically assured of getting it. After 1 b3, Black has equality without needing to do anything at all.

But that's a reason against spending too much time studying it, looking for an advantage which disappeared with White's first move. It's not a reason against actually playing it. Personally I have a huge record as White with 1 b3

jengaias wrote:

"All openings are completely equal nowadays. ..."

The December 2016 issue of Chess lists the top twenty openings compiled from a list of 2895 October games where both players were rated over 2400 Elo. One can not take position on this list too seriously because it is greatly influenced by how the openings are grouped. For example, all the Retis are grouped together, while English is separated into 1 ... c5, 1 ... e5, etc. Nevertheless, for what it is worth, some of the list entries report: 190 Retis, 133 King's Indians,108 Caro Kanns, 97 Nimzo-Indians, 94 Slavs, 88 Declined Queen's Gambits, 87 Najdorf Sicilians, 85 1...c5 Englishes, 67 Queen's Indians, 66 1...e5 Englishes, 60 1...Nf6 Englishes, 58 1...e6 Englishes, 56 Kan Sicilians, 52 Classical Gruenfelds, and 49 Semi-Slavs. Don't see any Nimzo-Larsen entry.