I have made a Nano send 4 pot values to an Uno please help with code
If your goal is to &quot;talk&quot; to a computer vs. a human, then a format that can be parsed easily is better than one that is easy to read.
For example, you have:
I received: 255
I received: 247
I received: 11
I received: 0

While this could be parsed by your Uno, it will be a lot simpler if you send the data something like:
255|247|11|0

Now you can use a &quot;C&quot; string parsing function like strtok() to parse on the &quot;|&quot; character.  Of course there are many other ways to do this as well but this is one possible solution to your question.