Unfortunately, Node-RED is not really designed to be a dashboard or control panel, and AFAIK there are no plans to move that direction (https://groups.google.com/d/msg/node-red/IJAzy233EWE/dn6c5G5Mdh0J).
However, with some creativity and time, you can create dashboards to display data and control panels to send and receive commands using Node-RED to build endpoints and connections between data sources, see Jeff's answer and search npm for similar projects.
You will need to see if BigSheets can export data, hopefully via a REST endpoint. You specifically seem to be wanting to display the actual charts (as an image) as opposed to the data. I have no idea if this is possible, but it doesn't look like it. You can maybe do something by manually extracting the data [1] every so often, or go all out and build a Big SQL application [2].
[1] http://www-01.ibm.com/support/knowledgecenter/SSPT3X_4.0.0/com.ibm.swg.im.infosphere.biginsights.tut.doc/doc/tut_less_bigsheets_exporting.html
[2] http://www-01.ibm.com/support/knowledgecenter/SSPT3X_4.0.0/com.ibm.swg.im.infosphere.biginsights.tut.doc/doc/tut_intro_bigsql.html