Nope. This is one of the drawbacks to using a laptop for livestreaming. You have to choose between Display Capture, or Game+Window Capture.
You could always just window capture your browser (assuming you aren't using Edge for some reason).
Please note that most 'reaction' streams are very likely illegal due to copyright infringement, even if they aren't being prosecuted at present. 'Fair use' doesn't cover watching+restreaming someone else's content and making faces.