I assume the answer is currently no and can probably survive with alt tabbing around.
In the old version of Big Picture you could bring up a browser in the Steam overlay while playing mid game. This allowed for quickly accessing online references and even bookmarking online guides etc.
I’m aware of accessing Steam guides and notes - and these are great features. But is there a way to easily access online information while playing?
Ok, sorry for the misinformation. In the beta there actually was a Browser available but since then it has been removed and there are currently no ways to reenable it.