You'd be breaking your NDA by releasing homebrew cia's from the SDK. As far as whether they'd go after you is another story - the 3ds isn't a big priority for them now. They don't even sell 3ds dev hardware anymore.
One thing is for certain though, you won't make a red cent selling your homebrew that way. The 3ds is not a viable commercial platform anymore, even if you somehow sell legit. It's 10 years old.