With two ESCs if they have BECs fitted you need to disconnect the red lead to the receiver on one of them otherwise the receiver gets confused.
You can run both off one channel with a mixer (Action do one - others are available) or have one channel each in which case you will need a 4+ channel set up.
I was advised, many years ago, that it is also better to run each off a separate battery, particularly with a mixer. I have done so ever since with no problems.
Good luck
