Oh, but I can.

1) Three recent Nintendo ads?
Here you go.
And another.
And yet another.

2) General Wii U ads?
Boom.
As far as Wii U ads about the console itself go, I can’t find another one. So you got me there! Cheers to you! Wii U ads about its games are much more common, though… which brings me to part 3.

3) Another ad for a Wii U game?
Right here.
Also, have this as a bonus.
And this.

4) A not-Pokemon 3DS ad? I'll do you better and give you three.
Bam.
Boom.
Ba-ba-boom.

Oh, and these are just USA commercials. There’s dozens more examples of modern Nintendo ads, be it TV or in-store, out there in other countries. Japan, in particular, is full of this stuff.

You may argue that Nintendo doesn't do enough gaudy billboard ads like this Splatoon one (and you do have a point), but to say that they don't advertise their games period just because you can't name any immediate examples? That’s pretty damn narrow-minded.