A bigger nozzle will allow thicker layers and reduce print time (and resolution.) However there are some caveats and limits to how big you might want to make the nozzle.
The MOARstruder has a 1.2mm nozzle and a longer heater block to support the extra volume of melted plastic its speed requires. I suspect/guess that a 1.4mm nozzle if you could find one would outpace the stock heater block at normal print speeds let alone high ones. (A theoretical 1.4mm nozzle would put out 7.84x the volume of .5mm nozzle, a huge difference…1.2mm is “just” 5.76x and they changed the hot end design.)
The speed referenced by Piercet above was for the overall motion system (X/Y). This is related to but distinct from the layer height and amount of plastic per unit time.
Based on your comments so far, it isn’t clear that you have tried the advice of adjusting the speeds in the slicer. Have you? You referenced doing this, but I don’t know if you were able to reach suitable print speed with the knob after the print starts? I have found that this method works at least when printing from SD card but I didn’t test it since switching to OctoPrint.
If despite this you do get such a nozzle and slap it on there, please post an update or video because I would be interested to see it. I’ve never tried something like that myself. (Though I do have a MOARstruder.)