Yeah, fitting the engine won't be an issue, it's the NATS ECU that will not work. If the 1.3 does not have NATS and you use the ignition barrel off the 1.3 surely it should be ok? So you end up with a non-NATS car altogether?
I'm not going to do all the work for you, but look around the net, there's diagrams of k11 ecu pin outs, find non-nats and nats, and then spot the differences.
i have done both the 1.3 bits into a 1.0 (click here) (works fine but is expensive to re-build the engine) and swapped a 1.3 non nats into a 1.0 nats, i used the standard 1.0nats ecu for the latter, but you could fit a 1.3 ecu with nats and get nissan to recode your keys, or fit the transponder pick up ring around the ignition barrel from the 1.3 nats ecu and swap over the chips in the keys. this should work in theory. or as mentioned above, re wire the ecu wiring so that you can use a non nats 1.3 ecu.