Tails and Whonix both can run in VirtualBox. Tails doesn't recommends it for security reasons (https://tails.boum.org/doc/advanced_topics/virtualization/index.en.html), for Whonix it seems to be a standard mode of operation.
What are the design differences which makes Whonix more secure to use it together with VirtualBox in comparison to Tails?
See also: