Shearing a wall smart DYI project?
There are a lot of details to consider, but if you can follow plans you can probably get it done.
Last year I designed a garage myself but needed to have the front wall engineered for both wind load and shear.  I tried to do the calcs myself but the city wanted a structural engineer to sign off on it.
Anyhow, while the plans weren't that complex on paper, building such a large wall and doing some more complicated framing up high was a big job but I got it done.
So if you have the specs, and can follow that you'll be fine.
There are so many variations on shear walls it's too hard to say just how easy or complicated it may be.  Some require additional fastening to the foundation, some require a lot of metal strapping.  Some require structural sheathing to be used on both sides of the wall or a closer nailing pattern.
I'd say give it a go!