You can store the incoming data to a database or depending how many points your chart is showing a context variable. You can then restore your chart using the saved data.
If you require more help i suggest you show an example of your incoming data (in text form) and an export of your flow. You can use the debug sidebar too copy data.
There’s a great page in the docs (Working with messages : Node-RED) that will explain how to use the debug panel to find the right path/value for any data item.
Pay particular attention to the part about the buttons that appear under your mouse pointer when you over hover a debug message property in the sidebar.
In order to make code readable and usable it is necessary to surround your code with three backticks (also known as a left quote or backquote ```)
```
code goes here
```
You can edit and correct your post by clicking the pencil 
icon.
See this post for more details - How to share code or flow json
