Microsoft invested $300 million into Barnes & Noble last year to create the Nook media subsidiary. Now the company may be looking to outright acquire the subsidiary from the national bookstore chain.

TechCrunch is reporting that Microsoft has offered to buy Nook Media from Barnes & Noble for a cool $1 billion. The information came from internal documents that also revealed the bookstore’s plans to completely renovate the Nook brand next year.

Aside from the Microsoft acquisition, the documents also say that Nook is planning on ditching its Android-based Nook HD and HD+ tablets in 2014. It’s a little strange considering that Nook just pushed the Google Play store onto these tablets, but it would be part of a larger move that would see Nook going mostly digital. In other words, Nook would be another third-party app on other devices with no dedicated hardware for itself.

Speaking of hardware, it seems that Nook may continue making e-readers despite ditching the tablet business. The logic here is that Nook will follow the gradual decline in e-reader sales while milking the business for as long as it can.

While that’s all well and interesting, the big news is here is a Microsoft buyout. It would only make sense, especially with Nook’s intention to go all digital, as Microsoft needs a killer app for its Windows 8 tablets. There’s already a Nook app for Windows 8, but a Microsoft-controlled and curated Nook app would be right up the Redmond-based company’s alley. It would also help the company compete with Amazon, Google and Apple – all of which operate their own e-book stores.

What makes this more interesting is the suggestion that Microsoft will be introducing a smaller Windows 8 tablet later this year alongside Windows Blue. A Microsoft-branded Nook app launching with Windows Blue could work wonders with a marketing campaign focusing on how Windows 8 provides music, movies and books from the Start menu.

Of couse, we can’t forget that a Microsoft buyout would fit well with Barnes & Noble founder Leonard Riggio’s plans to buy the Barnes & Noble retail operation while ditching the Nook business. Both could work together to ensure that Microsoft takes on the digital operation while Riggio can procede with his plans to take Barnes & Noble private.