How do you chart individual investment or stocks within an account?

No, there is limited charting in Quicken Mac at this point in its development. The chart at the top of the Portfolio screen charts the account, but not individual stocks (nor any indexes, like S&P 500). 

There are a couple Idea threads requesting more advanced charting options. You should add your vote and comments to one or both…

https://community.quicken.com/discussion/7850195/select-securities-to-graph-from-investment-accounts

https://community.quicken.com/discussion/7384359/view-price-history-graph-for-a-security-22-legacy-votes