um.. i dont know, but that hiragana ain't look like nyan.
Its more like tayun XD

That's correct, it does say tayun, which I think is a 'boing' type sound effect. whoever added the note clearly made an assumption as to what it said >.>

I don't make a habit of that, but yeah, I completely neglected to actually read the simple, kindergarten-level hiragana, and just typed "nyan ♡".