Streaming set up using a Mac mini

My situation isn't ideal (I know that). I want to stream a relatively demanding game to twitch. However I have a Mac mini and a MacBook Pro, both not ideal for gaming. They can play the games but I think streaming and gaming on the same mac will be too much. Until I can afford a gaming pc (probably going to be awhile) I've decided that the best way to do this is to use both computers, the MacBook Pro for gaming and the mini for the streaming. My issue is getting the MacBook Pro video output into the Mac mini. Is there anyway of doing this or is a capture card my best/cheapest option?

Any information/advice to get around my problem will be ideal

Thanks!!