No, this is not possible because Godot does not integrate something like CEF (Chromium Embedded Framework). There are many reasons for this (those frameworks are usually large in file size, not always very secure, and most games don't need it).
You are better off doing something like receiving BBCode from a website and formatting it in RichTextLabel. Alternatively, you could develop a C++ module for your own use (using CEF), but this is far from trivial.
