I am really interested in this too. I’m wanting to get Mosquito, node.js and Node-Red working to make an IoT Broker.
Most folks are using Raspberry Pi for this at present.
I got a version just about working on another router following Chris Swan’s work at Node-RED on WRTnode | Chris Swan's Weblog
but using a USB stick is not ideal.
Any help, pointers or tips would be most welcome as I’m pretty green on Open-wrt.