Assuming you are looking to "pop and bang" during decel this info may help you.
Nismotronic has whats called TPS closed timing table's. To find it you navigate like so, Idle tab > Idle > Ignition
You will then see the check box to enable TPS closed timing table. This should be enabled. You can modify ignition vs rpm up to 3,000 RPM here. Anything out of that range, I would assume would be handled by the primary ignition map.
Are you using a MAP or MAF as your primary load source? If it happens to be a MAP you can easily achieve the "banging and popping" during decel though the standard fuel and ignition maps. If it is a MAF, and you are not using your other secondary load source, you could set your car up to idle and decel using the MAP sensor.