Question Ryzen 5 2600x and rtx 2070 or ryzen 7 2700x and rtx 2060 for gaming and streaming at about 2k and 144 fps?

I'm assuming you mean Game Streaming to Twitch right?

If so, you really need to look up what those two codecs are.

Simply put:

x264 uses the CPU to compress your games frames and send them to your stream.
NVENC uses your GPU instead.

I recommend you start with NVENC, it has far less of a performance impact vs x264 and looks basically just as good.