Beyond just having multiple browser tabs open at a time, Coinigy allows users to "add" more symbols to the chart which is our version of the multi-chart view. To do so, first, click the "scale" icon on top of the chart, and choose 'Add Symbol' (Note the dark blue arrows and circles indicating what to click in each step).
You can then search for the symbol you'd like to add (In this case, BTC/USD is what we start with and we are adding ETH/BTC).
Once it's added to the chart, change the type to "candles".
And then choose to unmerge the symbol down.
This will place the new symbol directly underneath your currently open symbol.