What printer and nozzles are you using?
Did you damage the thermistor or the heater cartridge during the first nozzle swap? Could be that damage is preventing it from getting/staying at the correct temperature.
Did you double check the slicer settings are correct?
There’s also a setting for minimum spacing between parts. The default is overly cautious iirc, I’d suggest lowering it and trying again, though I don’t expect it to change much