Hi, nookfan. And welcome to the Forums.
No, B&N can not add the Toca Boca apps to their store. However, Toca Boca can do so. You could contact them in their Forums at http://tocaboca.uservoice.com and suggest it to them. Since they seem to be mostly kids games, I'm sure that B&N would welcome them with open arms.
However, I have to caution you that so far all their stuff is only on the Mac. And porting it to Android might be a fair amount of work, which they'd probably want to do first, before making them available on the Nooks. Android does seem to be their most requested item though...
"At the moment, we only have products for iPhone, iPod Touch and iPad. But we think that the important thing when making games for kids is the touchscreen, rather than the manufacturer. So if enough people want them on Android we will speed up that process."