I'm not familiar with MQTT, I've just glanced over the spec right now.
Nchan is basically a message broker with channels, optimized for message broadcast.
MQTT is a TCP-level protocol, whereas all the currently implemented subscriber clients for Nchan are HTTP-level (Longpoll, EventSource and Websocket, which begins with an HTTP request). MQTT subscribers and publishers could be implemented in nchan, but I haven't yet written any raw-TCP connection negotiation code, so I don't know how hard it would be. Aside from that, the subscriber code is very modular and adding another protocol like MQTT would be straightforward.
Nchan is basically a message broker with channels, optimized for message broadcast.
MQTT is a TCP-level protocol, whereas all the currently implemented subscriber clients for Nchan are HTTP-level (Longpoll, EventSource and Websocket, which begins with an HTTP request). MQTT subscribers and publishers could be implemented in nchan, but I haven't yet written any raw-TCP connection negotiation code, so I don't know how hard it would be. Aside from that, the subscriber code is very modular and adding another protocol like MQTT would be straightforward.